TY - JOUR
TI - TOWARD SPECIALIZED UNDERGRADUATE TELECOMMUNICATION ENGINEERING EDUCATION IN THE US
AU - El-Bawab, Tarek S.
AU - Esfandiari, Mehran
AU - Rouskas, George
AU - Jayasumana, Anura
AU - Kincaid, Michael
AU - Effenberger, Frank
AU - Kazovsky, Leonid
AU - Medard, Muriel
AU - Frost, Victor
AU - Baniewicz, Paul
T2 - Ieee Communications Magazine
DA - 2012///
PY - 2012///
VL - 50
IS - 9
SP - 14-16
ER -
TY - CONF
TI - Performance of an Iterative Production Planning Approach for Production Systems with Manufacturing Flexibility
AU - Albey, E.
AU - Bilge, U.
AU - Uzsoy, R.
T2 - Workshop on Production Economics
C2 - 2012/2//
CY - Innsbruck, Austria
DA - 2012/2//
PY - 2012/2//
ER -
TY - CONF
TI - Modeling for Equitable Food Distribution Under Capacity Constraints
AU - Ivy, J.S.
AU - Sengul, I.
AU - Uzsoy, R.
T2 - Industrial and Systems Engineering Research Conference
C2 - 2012/5//
CY - Orlando, FL
DA - 2012/5//
PY - 2012/5//
ER -
TY - CONF
TI - Engineering Process Improvement for Wafer Fabrication
AU - Kim, S.
AU - Uzsoy, R.
T2 - 23rd Advanced Semiconductor Manufacturing Conference
C2 - 2012/5//
CY - Saratoga Springs, NY
DA - 2012/5//
PY - 2012/5//
ER -
TY - JOUR
TI - Multiple Time Scales in Production Planning: Clearing Functions, Discrete-Event Simulation and Partial Differential Equations
AU - Armbruster, D.
AU - Uzsoy, R.
T2 - Tutorials in Operations Research
DA - 2012///
PY - 2012///
ER -
TY -
ER -
TY - BOOK
TI - Optimizing Risk Management in Services
A3 - Fang, S.
A3 - Wu, D.
A3 - Olson, D.L.
A3 - Birge, J.R.
DA - 2012///
PY - 2012///
VL - 61
ER -
TY - BOOK
TI - The First World Congress on Global Optimization in Engineering and Science
A3 - Floudas, A.
A3 - Fang, S.
A3 - Gao, David Y.
DA - 2012///
PY - 2012///
VL - 54
ER -
TY - JOUR
TI - Analysis on Transport Costs and China’s Exports
AU - Transport Costs, Analysis
AU - Exports, China’s
AU - Xu, L. Z.
AU - Wang, S.Y.
T2 - Systems Engineering Theory and Practice
DA - 2012///
PY - 2012///
VL - 32
IS - 5
SP - 1057–1067
ER -
TY - BOOK
TI - Discrete and Continuous Dynamical Systems, Series B: Mathematical Modeling, Analysis and Computations
A3 - Li, Zhilin
DA - 2012/6//
PY - 2012/6//
VL - 17
M3 - Special Issue dedicated to Thomas Beale and the FAN conference
ER -
TY - JOUR
TI - Simplified immersed interface methods for elliptic interface problems with straight interfaces
AU - Feng, Xiufang
AU - Li, Zhilin
T2 - Numerical Methods for Partial Differential Equations
AB - In this article, we propose simplified immersed interface methods for elliptic partial/ordinary differential equations with discontinuous coefficients across interfaces that are few isolated points in 1D, and straight lines in 2D. For one-dimensional problems or two-dimensional problems with circular interfaces, we propose a conservative second-order finite difference scheme whose coefficient matrix is symmetric and definite. For two-dimensional problems with straight interfaces, we first propose a conservative first-order finite difference scheme, then use the Richardson extrapolation technique to get a second-order method. In both cases, the finite difference coefficients are almost the same as those for regular problems. Error analysis is given along with numerical example. © 2010 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 28: 188–203, 2012
DA - 2012/1//
PY - 2012/1//
DO - 10.1002/num.20614
VL - 28
IS - 1
SP - 188–203
SN - 0749-159X
UR - http://dx.doi.org/10.1002/num.20614
KW - conservative finite difference scheme
KW - discontinuous coefficient
KW - immersed interface method
KW - interface problem
KW - polar coordinates
KW - Richardson extrapolation
ER -
TY - BOOK
TI - Control and Optimization with Differential-Algebraic Constraints
T2 - Advances in Design and Control
A3 - Biegler, L.
A3 - Campbell, S.L.
A3 - Mehrmann, Volker
DA - 2012///
PY - 2012///
PB - Society for Industrial and Applied Mathematics
SN - 9781611972245
ER -
TY - CHAP
TI - Commitments in Multiagent Systems: Some History, Some Confusions, Some Controversies, Some Prospects
AU - Singh, Munindar P.
T2 - The Goals of Cognition: Essays in Honour of Cristiano Castelfranchi
A2 - Paglieri, Fabio
A2 - Tummolini, Luca
A2 - Falcone, Rino
A2 - Miceli, Maria
PY - 2012///
SP - 613–638
PB - College Publications
UR - https://www.csc2.ncsu.edu/faculty/mpsingh/papers/mas/Commitments-for-MAS.pdf
ER -
TY - CHAP
TI - A Note on Uncertainty in Real-Time Analytics
AU - Vouk, Mladen A.
T2 - Uncertainty Quantification in Scientific Computing. WoCoUQ 2011
A2 - Dienstfrey, A.M.
A2 - Boisvert, R.F.
T3 - FIP Advances in Information and Communication Technology
AB - Today real-time analytics of large data sets is invariably computer-assisted and often includes a “human-in-the-loop”. Humans differ from each other and all have a very limited innate capacity to process new information in real-time. This introduces statistical and systematic uncertainties into observations, analyses and decisions humans make when they are “in the loop”. Humans also have unconscious and conscious biases, and these can introduce (major) systematic errors into human assisted or human driven analytics. This note briefly discusses the issues and the (considerable) implications they can have on real-time analytics that involves humans, including software interfaces, learning, and reaction of humans in emergencies.
PY - 2012///
DO - 10.1007/978-3-642-32677-6_20
SP - 312–318
PB - Springer
SN - 9783642326769 9783642326776
SV - 377
UR - http://dx.doi.org/10.1007/978-3-642-32677-6_20
ER -
TY - CHAP
TI - Optimal Control Theory
AU - Tran, H.
T2 - Encyclopedia of Theoretical Ecology
A2 - Hastings, A.
A2 - Gross, L.
PY - 2012///
SP - 519–523
PB - University of California Press
SN - 9780520951785
ER -
TY - CONF
TI - A Kalman Filtering Based Approach for the Modeling of the Cardiovascular Regulation System
AU - Tran, H.
AU - Matzuka, B.
AU - Mehlsen, J.
AU - Olufsen, M.
AU - Williams, N.
T2 - International Workshop on Innovative Simulation for Healthcare
A2 - Backfrieder, W.
A2 - Bruzzone, A.
A2 - Longo, F.
A2 - Novak, V.
A2 - Rosen, J.
C2 - 2012///
C3 - Proceeding of The 1st international workshop on innovative simulation for healthcare, I-WISH
CY - Vienna, Austria
DA - 2012///
PY - 2012/9/19/
SP - 107–112
SN - 978-88-97999-13-3
ER -
TY - CONF
TI - Global Sensitivity and Identifiability Analysis Applied to a Model Predicting Baroreflex Regulation During Head-up Tilt
AU - Olsen, C.H.
AU - Mehlsen, J.
AU - Otteson, J.
AU - Tran, H.
AU - Olufsen, M.S.
T2 - International Workshop on Innovative Simulation for Healthcare
A2 - Backfrieder, W.
A2 - Bruzzone, A.
A2 - Longo, F.
A2 - Novak, V.
A2 - Rosen, J.
C2 - 2012///
C3 - Proceeding of The 1st international workshop on innovative simulation for healthcare, I-WISH
CY - Vienna, Austria
DA - 2012///
PY - 2012/9/19/
SP - 81–86
SN - 978-88-97999-13-3
ER -
TY - JOUR
TI - Modeling Red Blood Cell and Iron Dynamics in Patients with Chronic Kidney Disease
AU - Banks, H.T.
AU - Bliss, K.M.
AU - Tran, H.
T2 - International Journal of Pure and Applied Mathematics
DA - 2012///
PY - 2012///
VL - 75
IS - 1
SP - 103–140
ER -
TY - BOOK
TI - Special Issue on Fluid Motion Driven by Immersed Structures
DA - 2012///
PY - 2012///
UR - https://www.researchgate.net/publication/296762774_Special_Issue_on_Fluid_Motion_Driven_by_Immersed_Structures_Preface
ER -
TY - BOOK
TI - SPECIAL ISSUE ON FLUID DYNAMICS, ANALYSIS AND NUMERICS
DA - 2012///
PY - 2012///
ER -
TY - CONF
TI - Infinite horizon periodic review perturbed demand model with lead time
AU - Lavin, J.A.
AU - King, R.E.
AU - Vila-Parrish, A.R.
AU - Warsing, D.P.
AU - Ahiska, S.S.
C2 - 2012///
C3 - 62nd IIE Annual Conference and Expo 2012
DA - 2012///
SP - 540-547
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84900339479&partnerID=MN8TOARS
ER -
TY - CONF
TI - An inventory model with restricted replenishment opportunities and re-estimated demand
AU - Buch, N.
AU - King, R.E.
AU - Vila-Parrish, A.R.
AU - Warsing, D.P.
C2 - 2012///
C3 - 62nd IIE Annual Conference and Expo 2012
DA - 2012///
SP - 531-539
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84900300196&partnerID=MN8TOARS
ER -
TY - CONF
TI - Unreliable supplier selection with fixed costs and order constraints
AU - Wang, Y.
AU - Warsing, D.P.
AU - King, R.E.
AU - Vila-Parrish, A.
AU - Sebnem Ahiska, S.
C2 - 2012///
C3 - 62nd IIE Annual Conference and Expo 2012
DA - 2012///
SP - 280-289
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84900342003&partnerID=MN8TOARS
ER -
TY - JOUR
TI - Preface
AU - Fang, Shu-Cherng
AU - Floudas, Christodoulos A.
AU - Gao, David Y.
T2 - Journal of Global Optimization
DA - 2012/9/12/
PY - 2012/9/12/
DO - 10.1007/S10898-012-9977-1
VL - 54
IS - 2
SP - 219-220
J2 - J Glob Optim
LA - en
OP -
SN - 0925-5001 1573-2916
UR - http://dx.doi.org/10.1007/S10898-012-9977-1
DB - Crossref
ER -
TY - JOUR
TI - A multi-agent simulation of the pharmaceutical supply chain
AU - Jetly, G
AU - Rossetti, C L
AU - Handfield, R
T2 - Journal of Simulation
AB - The pharmaceutical supply chain is composed of multiple firms interacting to produce and distribute drugs in an uncertain environment. In this work, we develop and validate a multi-agent simulation of the supply chains associated with the pharmaceutical industry. We demonstrate that the operating norms of a particular industry can be accurately represented to create an industry-specific model capable of tracing its evolution. Our model is initialized using 1982 financial data with 30 manufacturers, 60 suppliers, and 60 distributors. Three types of drugs, blockbusters, medium and small, with a 12-year lognormal product life cycle are released by manufacturers. Each quarter the distributors bid for future market share of the released products, and the suppliers bid for acceptable margins. Mergers and acquisitions, based on assets and expected profitability, are allowed at each level. One thousand replications, each lasting the equivalent of 39 years, are used to validate the model.
DA - 2012/11//
PY - 2012/11//
DO - 10.1057/jos.2011.26
VL - 6
IS - 4
SP - 215-226
J2 - Journal of Simulation
LA - en
OP -
SN - 1747-7778 1747-7786
UR - http://dx.doi.org/10.1057/jos.2011.26
DB - Crossref
KW - multi-agent simulation
KW - pharmaceutical
KW - supply chain
KW - industrial relations
KW - medicine
ER -
TY - CONF
TI - Probabilistic Mapping of Water Leakage Characterizations Using a Bayesian Approach
AU - Barandouzi, M. A.
AU - Mahinthakumar, G.
AU - Ranjithan, R.
AU - Brill, E. D.
T2 - World Environmental And Water Resources Congress 2012
AB - Water Distribution Systems are one of the most substantial and vulnerable part of civil infrastructure systems. For the reason that many large water distribution systems are old, which results in more leakage and expenses (e.g., increasing pump head, pipe burst, constituents' replacement), a significant portion of water produced by the utilities never passes through the consumers' meters. Due to the complex nature and vast spatial extent of a water distribution system it may be difficult for the utility personnel to identify and fix the leaks, therefore it is imperative to develop software frameworks for modeling and analyzing leakage in water distribution system during ordinary operational conditions as well as unexpected events. In this paper a Bayesian approach with Markov chain Monte Carlo method is implemented to map probabilistic characterizations of water leakage. If for this purpose physical parameters such as pipe vintage, material, and loading are available, they can be are used to develop prior information; otherwise, a uniform prior may be assumed. Routinely measured water quality, pressure, and flow measurements together with the uncertainty in demand are used to develop the likelihood function. The analyses are facilitated through the EPANET water distribution simulation tool. The efficiency and versatility of the proposed methodology is examined using water distribution network.
C2 - 2012/5/17/
C3 - World Environmental and Water Resources Congress 2012
DA - 2012/5/17/
DO - 10.1061/9780784412312.326
PB - American Society of Civil Engineers
SN - 9780784412312
UR - http://dx.doi.org/10.1061/9780784412312.326
DB - Crossref
ER -
TY - CONF
TI - Parallel Multi-Swarm Optimization Framework for Search Problems in Water Distribution Systems
AU - Sreepathi, Sarat
AU - Brill, Downey
AU - Ranjithan, Ranji
AU - Mahinthakumar, Gnanamanikam (Kumar)
T2 - World Environmental And Water Resources Congress 2012
AB - Population based heuristic search methods such as evolutionary algorithms (EA) and particle swarm optimization (PSO) methods are widely used for solving optimization problems especially when classical techniques are inadequate. A parallel optimization framework using multiple concurrent particle swarms is developed and applied to water distribution problems. Details of the enabling framework that couples the optimization methods with a parallel simulator built around EPANET will be discussed. In addition, algorithmic and computational performance results using ORNL’s and ANL’s leadership class parallel architectures will be presented for leakage detection and contaminant source characterization problems for two water distribution networks with 1,834 and 12,457 nodes respectively.
C2 - 2012/5/17/
C3 - World Environmental and Water Resources Congress 2012
DA - 2012/5/17/
DO - 10.1061/9780784412312.323
PB - American Society of Civil Engineers
SN - 9780784412312
UR - http://dx.doi.org/10.1061/9780784412312.323
DB - Crossref
ER -
TY - CHAP
TI - Deterministic View Selection for Data-Analysis Queries: Properties and Algorithms
AU - Huang, Rong
AU - Chirkova, Rada
AU - Fathi, Yahya
T2 - Advances in Databases and Information Systems
AB - The view-selection problem is a combinatorial optimization problem that arises in the context of on-line analytical processing (OLAP) in database management systems. We pose the problem as an integer programming (IP) model, study its structural properties, and propose effective techniques for reducing the search space of views and thus the size of the corresponding IP model. We then use these results to design both exact methods and heuristic algorithms that are effective for solving relatively large realistic-size instances of the problem.
PY - 2012///
DO - 10.1007/978-3-642-33074-2_15
SP - 195-208
OP -
PB - Springer Berlin Heidelberg
SN - 9783642330735 9783642330742
UR - http://dx.doi.org/10.1007/978-3-642-33074-2_15
DB - Crossref
ER -
TY - JOUR
TI - Patient-based pharmaceutical inventory management: a two-stage inventory and production model for perishable products with Markovian demand
AU - Vila-Parrish, Ana R
AU - Ivy, Julie S
AU - King, Russell E
AU - Abel, Steven R
T2 - Health Systems
AB - Drug shortages have increased over the past decade, tripling since 2006. Pharmacy material managers are challenged with developing inventory policies given changing demand, limited suppliers, and regulations affecting supply. Pharmaceutical inventory management and patient care are inextricably linked; suboptimal control impacts both patient treatment and the cost of care. We study a perishable inventory problem motivated by challenges in pharmaceutical management. Inpatient hospital pharmacies stock medications in two stages, raw material and finished good (e.g. intravenous). While both stages of material are perishable, the finished form is highly perishable. Pharmacy demand depends on the population and patient conditions. We use a stochastic ‘demand state’ as a surrogate for patient condition and develop a Markov decision process to determine optimal, state-dependent two-stage inventory and production policies. We define two ordering and production scenarios, prove the existence of optimal solutions for both scenarios, and apply this framework to the management of Meropenem.
DA - 2012/6//
PY - 2012/6//
DO - 10.1057/hs.2012.2
VL - 1
IS - 1
SP - 69-83
J2 - Health Systems
LA - en
OP -
SN - 2047-6965 2047-6973
UR - http://dx.doi.org/10.1057/hs.2012.2
DB - Crossref
KW - Markov decision process
KW - perishable inventory
KW - pharmacy
KW - medication inventory management
ER -
TY - BOOK
TI - Towards argumentation with symbolic dempster-shafer evidence
AU - Tang, Y.
AU - Hang, C.-W.
AU - Parsons, S.
AU - Singh, M.
AB - This paper is concerned with the combination of argumentation with the Dempster-Shafer theory of evidence. In particular, we show how logical elements of evidence, associated with numerical degrees of belief, can be combined into arguments.
DA - 2012///
PY - 2012///
DO - 10.3233/978-1-61499-111-3-462
VL - 245
SE - 462-469
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84876280338&partnerID=MN8TOARS
ER -
TY - BOOK
TI - The evolution of interoperability
AU - Chopra, A.K.
AU - Singh, M.P.
AB - This note is a retrospective review of our 2006 paper [1] on the properties of protocols, especially interoperability. A bit of history is in order. By 2006, the importance of a social semantics for protocols was well-established in the multiagent systems community. Further, commitments had emerged as a preeminent abstraction for capturing the semantics. The big advantage was that specifying the meaning of protocol messages in terms of the commitments among agents enabled the agents to act flexibly.
DA - 2012///
PY - 2012///
DO - 10.1007/978-3-642-29113-5_8
VL - 7169 LNAI
SE - 90-94
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84859360981&partnerID=MN8TOARS
ER -
TY - JOUR
TI - Specifying and verifying cross-organizational business models: An agent-oriented approach
AU - Telang, P.R.
AU - Singh, M.P.
T2 - IEEE Transactions on Services Computing
AB - Cross-organizational business processes are routine in today's economy. Of necessity, enterprises conduct their business in cooperation to create products and services for the marketplace. Thus business processes inherently involve autonomous partners with heterogeneous software designs and implementations. Therefore, it would be natural to model such processes via high-level abstractions that reflect the contractual relationships among the business partners. Yet, in today's IT practice, cross-organizational processes are modeled at a low level of abstraction in terms of the control and data flow among the participants. This paper makes the following contributions. First, it proposes a simple, yet expressive, declarative way to specify business models at a high level based on the notion of commitments. Second, it shows how such a high-level model maps to a conventional operational model. Third, it provides a basis for verifying the correctness of the operational representations with respect to the declarative business model using existing temporal model checking tools. This paper validates the above claims using the well-known Quote To Cash business process, e.g., as supported by vendors such as SAP and applied in large enterprises. In this manner, this paper helps bridge the gap between high-level business models and their IT realizations.
DA - 2012///
PY - 2012///
DO - 10.1109/TSC.2011.4
VL - 5
IS - 3
SP - 305-318
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84865693874&partnerID=MN8TOARS
KW - Methodologies
KW - patterns
KW - specification
KW - model checking
ER -
TY - CONF
TI - Semantics and Verification of Information-Based Protocols
AU - Singh, Munindar P.
T2 - The 11th International Conference on Autonomous Agents and Multiagent Systems
C2 - 2012/6//
C3 - AAMAS '12: Proceedings of the 11th International Conference on Autonomous Agents and Multiagent Systems
CY - Valencia, Spain
DA - 2012/6//
PY - 2012/6/4/
VL - 2
SP - 1149–1156
PB - IFAAMAS
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84899461141&partnerID=MN8TOARS
ER -
TY - BOOK
TI - Relating goal and commitment semantics
AU - Telang, P.R.
AU - Singh, M.P.
AU - Yorke-Smith, N.
AB - Whereas commitments capture how an agent relates with another agent, (private) goals describe states of the world that an agent is motivated to bring about. Researchers have observed that goals and commitments are complementary, but have not yet developed a combined operational semantics for them. This paper makes steps towards such a semantics by relating the respective lifecycles of goals and commitments. We study how the the concepts cohere for one agent and how they engender cooperation between agents. We illustrate our approach via a real-world scenario in the domain of aerospace aftermarket services. We state how our semantics yields important desirable properties, including convergence of the configurations of cooperating agents, thereby delineating some theoretically well-founded yet practical modes of cooperation in a multiagent system.
DA - 2012///
PY - 2012///
DO - 10.1007/978-3-642-31915-0_2
VL - 7217 LNAI
SE - 22-37
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84864839657&partnerID=MN8TOARS
ER -
TY - CONF
TI - Comma: A Commitment-Based Business Modeling Methodology and its Empirical Evaluation
AU - Telang, Pankaj R.
AU - Singh, Munindar P.
T2 - The 11th International Conference on Autonomous Agents and Multiagent Systems
C2 - 2012/6//
C3 - AAMAS '12: Proceedings of the 11th International Conference on Autonomous Agents and Multiagent Systems
CY - Valencia, Spain
DA - 2012/6//
PY - 2012/6/4/
VL - 2
SP - 1073–1080
PB - IFAAMAS
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84899460865&partnerID=MN8TOARS
ER -
TY - JOUR
TI - Agent-based organisational governance of services
AU - Brazier, F.
AU - Dignum, V.
AU - Huhns, M.N.
AU - Derksen, C.
AU - Dignum, F.
AU - Lessner, T.
AU - Padget, J.
AU - Quillinan, T.
AU - Singh, M.P.
T2 - Multiagent and Grid Systems
AB - The objective of service-oriented computing (SOC) is to construct software applications out of appropriate services available and executing in place anywhere across the Web. To achieve this objective requires that techniques for discovering and engag
DA - 2012///
PY - 2012///
DO - 10.3233/MGS-2012-0187
VL - 8
IS - 1
SP - 3-18
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84859083383&partnerID=MN8TOARS
KW - Institutions
KW - multi-agent systems
KW - organisations
KW - service engagements
KW - service enactment
KW - governance model
ER -
TY - CHAP
TI - Emerging Properties of Knowledge Sharing Referral Networks: Considerations of Effectiveness and Fairness
AU - Manavalan, Priyadarshini
AU - Singh, Munindar P.
T2 - Lecture Notes in Computer Science
AB - Referral-based peer-to-peer networks have a wide range of applications. They provide a natural framework in which agents can help each other. This paper studies the trade-off between social welfare and fairness in referral networks. The traditional, naive mechanism yields high social welfare but at the cost of some agents--in particular, the best ones--being exploited. Autonomous agents would obviously not participate in such networks. An obvious mechanism such as reciprocity improves fairness but substantially lowers welfare. A more general incentive mechanism yields high fairness with only a small loss in welfare. This paper considers substructures of the network that emerge and cause the above outcomes.
PY - 2012///
DO - 10.1007/978-3-642-31809-2_2
VL - 6573 LNAI
SP - 13-23
OP -
PB - Springer Berlin Heidelberg
SN - 9783642318085 9783642318092
UR - http://dx.doi.org/10.1007/978-3-642-31809-2_2
DB - Crossref
ER -
TY - CONF
TI - Collaborative assessment of functional reliability in wireless networks
AU - Feng, Zi
AU - Pelechrinis, Konstantinos
AU - Krishnamurthy, Srikanth
AU - Swami, Ananthram
AU - Wu, Felix
AU - Singh, Munindar P.
T2 - 2012 IEEE 9th International Conference on Mobile Ad-Hoc and Sensor Systems (MASS)
AB - Nodes that are part of a multihop wireless network, typically deployed in mission critical settings, are expected to perform specific functions. Establishing a notion of reliability of the nodes with respect to each function (referred to as functional reliability or FR) is essential for efficient operations and management of the network. This is typically assessed based on evidence collected by nodes with regards to other nodes in the network. However, such evidence is often affected by factors such as channel induced effects and interference. In multihop contexts, unreliable intermediary relays may also influence evidence. We design a framework for collaborative assessment of the FR of nodes, with respect to different types of functions; our framework accounts for the above factors that influence evidence collection. Each node (say Chloe) in the network derives the FR of other nodes (say Jack) based on two types of evidence: (i) direct evidence, based on her direct transactions with each such node and (ii) indirect evidence, based on feedback received regarding Jack from others. Our framework is generic and is applicable in a variety of contexts. We also design a module that drastically reduces the overhead incurred in the propagation of indirect evidence at the expense of slightly increased uncertainty in the assessed FR values. We implement our framework on an indoor/outdoor wireless testbed. We show that with our framework, each node is able to determine the FR for every other node in the network with high accuracy. Our indirect evidence propagation module decreases the overhead by 37% compared to a simple flooding based evidence propagation, while the accuracy of the FR computations is decreased only by 8%. Finally, we examine the effect of different routing protocols on the accuracy of the assessed values.
C2 - 2012/10//
C3 - 2012 IEEE 9th International Conference on Mobile Ad-Hoc and Sensor Systems (MASS 2012)
DA - 2012/10//
DO - 10.1109/MASS.2012.6502543
SP - 425-433
PB - IEEE
SN - 9781467324335 9781467324335 9781467324328
UR - http://dx.doi.org/10.1109/mass.2012.6502543
DB - Crossref
ER -
TY - CONF
TI - Behind the curtain: Service selection via trust in composite services
AU - Hang, C.-W.
AU - Kalia, A.K.
AU - Singh, M.P.
AB - Service selection, where some of the services are accessed indirectly as constituents of composite services, is difficult for the following reasons: (1) the interpretation of service qualities is subjective; (2) evidence must be combined from multiple sources; (3) service profiles change dynamically; and (4) constituent services may be only partially observable behind composite services. We propose an approach where we map service qualities to a common probabilistic trust metric. Whereas current trust approaches estimate the trustworthiness of a composite service based on a fully observable and static setting, we propose a statistical approach built on expectation maximized over a finite mixture model. Our experiments show that our approach can dynamically punish or reward the constituents of composite services while making only partial observations.
C2 - 2012///
C3 - Proceedings - 2012 IEEE 19th International Conference on Web Services, ICWS 2012
DA - 2012///
DO - 10.1109/ICWS.2012.96
SP - 9-16
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84866358941&partnerID=MN8TOARS
ER -
TY - BOOK
TI - Argument schemes for reasoning about trust
AU - Parsons, S.
AU - Atkinson, K.
AU - Haigh, K.
AU - Levitt, K.
AU - McBurney, P.
AU - Rowe, J.
AU - Singh, M.P.
AU - Sklar, E.
DA - 2012///
PY - 2012///
DO - 10.3233/978-1-61499-111-3-430
VL - 245
SE - 430-441
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84876270149&partnerID=MN8TOARS
KW - Argument schemes
KW - critical questions
KW - trust
ER -
TY - JOUR
TI - A heuristic for bottleneck crossing minimization and its performance on general crossing minimization: Hypothesis and experimental study
AU - Stallmann, Matthias F
T2 - Journal of Experimental Algorithmics (JEA)
DA - 2012///
PY - 2012///
VL - 17
SP - 1-3
ER -
TY - JOUR
TI - Research Spotlights: New Opportunities for SIAM Review Authors
AU - Kelley, C T
AU - Tuminaro, Ray
T2 - SIAM News
DA - 2012///
PY - 2012///
ER -
TY - CONF
TI - Hybrid Deterministic/Monte Carlo Neutronics using GPU Accelerators
AU - Willert, Jeff
AU - Kelley, C T
AU - Knoll, D A
AU - Dong, H
AU - Ravishankar, M
AU - Sathre, P
AU - Sullivan, M
AU - Taitano, W
A2 - Guo, Qingping
A2 - Douglas, Craig
C2 - 2012///
C3 - 2012 International Symposium on Distributed Computing and Applications to Business, Engineering and Science
CY - Los Alamitos, CA
DA - 2012///
SP - 43--47
PB - IEEE
ER -
TY - JOUR
TI - A Mathematical Biography of {Danny C. Sorensen}
AU - Benner, Peter
AU - Embree, Mark
AU - Lehoucq, Richard B
AU - Kelley, C T
T2 - LAA
DA - 2012///
PY - 2012///
VL - 436
SP - 2717-2724
ER -
TY - JOUR
TI - Simulations of Light-Induced Molecular Transformations in Multiple Dimensions with Incremental Sparse Surrogates
AU - Mokrauer, David
AU - Kelley, C T
AU - Bykhovski, Alexei
T2 - J. Algorithms Comp Tech
DA - 2012///
PY - 2012///
VL - 6
IS - 4
SP - 577-592
ER -
TY - JOUR
TI - Inexact Levenberg-Marquardt with Reduced Order Models
AU - Winton, C
AU - Kelley, C T
AU - Eslinger, O J
AU - Hensley, J
AU - Hines, A
T2 - Water Resources Research
DA - 2012///
PY - 2012///
ER -
TY - JOUR
TI - Sparse interpolatory reduced-order models for simulation of light-induced molecular transformations
AU - Mokrauer, David
AU - Kelley, Carl
T2 - Optimization Methods and Software
AB - We describe a method for using interpolatory models to accurately and efficiently simulate molecular excitation and relaxation. We use sparse interpolation for efficiency and local error estimation and control for robustness and accuracy.
DA - 2012/7//
PY - 2012/7//
DO - 10.1080/10556788.2012.693928
VL - 29
IS - 2
SP - 1-10
UR - http://www.tandfonline.com/doi/abs/10.1080/10556788.2012.693928
ER -
TY - JOUR
TI - Research spotlights
AU - Ipsen, Ilse
T2 - SIAM Review
AB - A new section with a new direction. Research Spotlights replaced Expository Research Papers on January 31, 2012. Papers in Research Spotlights should cover topics in applied and computational mathematics of particularly wide interest and importance. Contributions must also be accessible to the broad and diverse SIAM Review readership. The principal theme of Research Spotlights is author flexibility with the intent that an expanded format promotes creativity and spurs innovative articles. Authors now have latitude in terms of considering a standard research paper or else a nontraditional article such as a mini-survey, a timely communication, a software description, or a new mathematical perspective within an application area. Prospective authors are encouraged to first consult with the section editor Ray Tuminaro (rstumin@sandia.gov) about potential contributions—especially those that lie outside the scope of traditional SIAM articles. While they can have a more relaxed format, ultimately articles must be of broad interest, must be accessible to the community, and must meet the technical review standards of SIAM journals. Focus groups provide feedback on potential new products: Which juice is more appealing to you, the slimy green or the yucky yellow one? Systems of sensors process signals to decide: Is there an intruder or not? These are examples of “group decision making,” a process where individuals work together to make a collective decision. The problem of figuring out how the collective arrives at a decision occurs in areas as varied as cognitive psychology, economics, political science, and signal processing. Margot Kimura and Jeff Moehlis in their paper “Group Decision-Making Models for Sequential Tasks” consider the “two-alternative forced-choice test,” where one must choose between two hypotheses: slimy green or yucky yellow; intruder or no intruder. Decisions must be made quickly and can only tolerate certain error rates. This means that there are limits on how often the sensors are allowed to miss an intruder, or signal a false alarm. The model in this paper assumes N independent decision makers, each of whom receives observations, sequentially, one at a time. Each decision maker continues to process the observations until s/he is able to make a decision. The incoming observations are represented by independent random variables, with known prior probabilities for each decision. The processing consists of applying the “sequential probability ratio test” to each new observation. Based on the prespecified error rates for the number of misses and false alarms, this test either reports a decision or continues to process the next observation. The authors also consider a continuous version of this test, which becomes a drift-diffusion model as the time between observations goes to zero. Once a decision maker has come up with a decision, s/he reports it to the “fusion center,” which is responsible for arriving at a collective decision. The fusion center can operate in one of three modes: race (report only the very first decision that arrives), majority-total (wait until all N decisions have arrived and then report the majority), and majority-first (wait until $N/2$ identical decisions have arrived, and then report this smallest possible majority). For each such mode, the authors derive probability distribution functions for the collective error rates and decision times, from the error rates and decision times of the individual decision makers. Simulations are presented to compare the different modes. Which mode turns out to be the most efficient is not at all obvious and depends on the scenario at hand, whether decision makers can have different error rates or can malfunction. Finally, the authors extend their analysis to more general modes, where the fusion center makes a collective decision based on the first $\eta$ decisions that arrive. The approach presented here has many advantages. It is general and applies to many situations that require collective decision making based on sequential observations, including even “cybernetic groups” with human observers and nonhuman detectors. Furthermore it is systematic and elegant, because it provides a clear path for deriving the efficiency of collective decisions from those of individual decision makers. Especially appreciated is a list of acronyms thoughtfully included by the authors at the beginning of the paper, which makes it easy to decipher the many acronyms in this area.
DA - 2012///
PY - 2012///
DO - 10.1137/SIREAD000054000001000119000001
VL - 54
IS - 1
SP - 119-120
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84861631122&partnerID=MN8TOARS
ER -
TY - BOOK
TI - Control and Optimization with Differential-Algebraic Constraints
A3 - Biegler, Lorenz T.
A3 - Campbell, Stephen L.
A3 - Mehrmann, Volker
AB - Differential-algebraic equations are the most natural way to mathematically model many complex systems in science and engineering. Once the model is derived, it is important to optimize the design parameters and control it in the most robust and efficient way to maximize performance. This book presents the latest theory and numerical methods for the optimal control of differential-algebraic equations. Readers will find the following features presented in a readable fashion so the results are accessible to the widest audience: the most recent theory, written by leading experts from a number of academic and nonacademic areas and departments, several state-of-the-art numerical methods, and real-world applications. Audience: This book is intended for applied mathematicians, engineers, and computational scientists from a variety of disciplines who are interested in the optimal control of problems. It will be of interest to those developing methods and theory and those working on real-world applications, especially in control and chemical and mechanical engineering. Contents: Chapter 1: DAEs, Control, and Optimization; Chapter 2: Regularization of Linear and Nonlinear Descriptor Systems; Chapter 3: Notes on Linearization of DAEs and on Optimization with Differential-Algebraic Constraints; Chapter 4: Spectra and Leading Directions for Linear DAEs; Chapter 5: StratiGraph Tool: Matrix Stratifications in Control Applications; Chapter 6: Descriptor System Techniques in Solving H2/Infinity-Optimal Fault Detection and Isolation Problems; Chapter 7: Normal Forms, High-Gain, and Funnel Control for Linear Differential-Algebraic Systems; Chapter 8: Linear-Quadratic Optimal Control Problems with Switch Points and a Small Parameter; Chapter 9: Mixed-Integer DAE Optimal Control Problems: Necessary Conditions and Bounds; Chapter 10: Optimal Control of a Delay PDE; Chapter 11: Direct Transcription with Moving Finite Elements; Chapter 12: Solving Parameter Estimation Problems with SOCX; Chapter 13: Control of Integrated Chemical Process Systems Using Underlying DAE Models; Chapter 14: DMPC for Building Temperature Regulation; Chapter 15: Dynamic Regularization, Level Set Shape Optimization, and Computed Myography; Chapter 16: The Application of Pontryagin s Minimum Principle for Endpoint Optimization of Batch Processes
DA - 2012/1//
PY - 2012/1//
DO - 10.1137/9781611972252
PB - Society for Industrial and Applied Mathematics
ER -
TY - CHAP
TI - Composite Interval Mapping and Multiple Interval Mapping: Procedures and Guidelines for Using Windows QTL Cartographer
AU - Silva, Luciano Da Costa E.
AU - Wang, Shengchu
AU - Zeng, Zhao-Bang
T2 - Methods in Molecular Biology
AB - Tremendous progress has been made in recent years on developing statistical methods for mapping quantitative trait loci (QTL) from crosses of inbred lines. In this chapter, we provide an introduction of composite interval mapping and multiple interval mapping methods for mapping QTL from inbred line crosses and also detailed instructions to perform the analyses in Windows QTL Cartographer. For each method, we discuss the meaning of each option in the analysis procedures and how to understand and interpret the mapping results through a work-out example.
PY - 2012///
DO - 10.1007/978-1-61779-785-9_6
SP - 75-119
OP -
PB - Humana Press
SN - 9781617797842 9781617797859
UR - http://dx.doi.org/10.1007/978-1-61779-785-9_6
DB - Crossref
ER -
TY - JOUR
TI - Metabolomics Reveals Amino Acids Contribute to Variation in Response to Simvastatin Treatment
AU - Trupp, Miles
AU - Zhu, Hongjie
AU - Wikoff, William R.
AU - Baillie, Rebecca A.
AU - Zeng, Zhao-Bang
AU - Karp, Peter D.
AU - Fiehn, Oliver
AU - Krauss, Ronald M.
AU - Kaddurah-Daouk, Rima
T2 - PLoS ONE
AB - Statins are widely prescribed for reducing LDL-cholesterol (C) and risk for cardiovascular disease (CVD), but there is considerable variation in therapeutic response. We used a gas chromatography-time-of-flight mass-spectrometry-based metabolomics platform to evaluate global effects of simvastatin on intermediary metabolism. Analyses were conducted in 148 participants in the Cholesterol and Pharmacogenetics study who were profiled pre and six weeks post treatment with 40 mg/day simvastatin: 100 randomly selected from the full range of the LDL-C response distribution and 24 each from the top and bottom 10% of this distribution (“good” and “poor” responders, respectively). The metabolic signature of drug exposure in the full range of responders included essential amino acids, lauric acid (p<0.0055, q<0.055), and alpha-tocopherol (p<0.0003, q<0.017). Using the HumanCyc database and pathway enrichment analysis, we observed that the metabolites of drug exposure were enriched for the pathway class amino acid degradation (p<0.0032). Metabolites whose change correlated with LDL-C lowering response to simvastatin in the full range responders included cystine, urea cycle intermediates, and the dibasic amino acids ornithine, citrulline and lysine. These dibasic amino acids share plasma membrane transporters with arginine, the rate-limiting substrate for nitric oxide synthase (NOS), a critical mediator of cardiovascular health. Baseline metabolic profiles of the good and poor responders were analyzed by orthogonal partial least square discriminant analysis so as to determine the metabolites that best separated the two response groups and could be predictive of LDL-C response. Among these were xanthine, 2-hydroxyvaleric acid, succinic acid, stearic acid, and fructose. Together, the findings from this study indicate that clusters of metabolites involved in multiple pathways not directly connected with cholesterol metabolism may play a role in modulating the response to simvastatin treatment. Trial Registration ClinicalTrials.gov NCT00451828
DA - 2012/7/9/
PY - 2012/7/9/
DO - 10.1371/journal.pone.0038386
VL - 7
IS - 7
SP - e38386
J2 - PLoS ONE
LA - en
OP -
SN - 1932-6203
UR - http://dx.doi.org/10.1371/journal.pone.0038386
DB - Crossref
ER -
TY - CHAP
TI - Chapter 10: Optimal Control of a Delay PDE
AU - Betts, John T.
AU - Campbell, Stephen L.
AU - Thompson, Karmethia C.
T2 - Control and Optimization with Differential-Algebraic Constraints
PY - 2012/1//
DO - 10.1137/9781611972252.ch10
SP - 213-231
OP -
PB - Society for Industrial and Applied Mathematics
SN - 9781611972245 9781611972252
UR - http://dx.doi.org/10.1137/9781611972252.ch10
DB - Crossref
ER -
TY - JOUR
TI - Simulations of Light-Induced Molecular Transformations in Multiple Dimensions with Incremental Sparse Surrogates
AU - Mokrauer, David
AU - Kelley, C. T.
AU - Bykhovski, Alexei
T2 - Journal of Algorithms & Computational Technology
AB - Simulations of light-induced molecular conformational transformations have traditionally been limited to a single degree of freedom because of the complexity of potential energy calculations. We propose a method of simulation that incrementally builds a surrogate for the potential energy function by computing gridpoints in parallel. We incorporate Smolyak's algorithm for sparse interpolation as the energy surrogates since it keeps the number of gridpoints at a manageable number. Our multi-dimensional algorithm is applied to the molecule 2-butene whose transition path is well known.
DA - 2012/12//
PY - 2012/12//
DO - 10.1260/1748-3018.6.4.577
VL - 6
IS - 4
SP - 577-592
J2 - Journal of Algorithms & Computational Technology
LA - en
OP -
SN - 1748-3018 1748-3026
UR - http://dx.doi.org/10.1260/1748-3018.6.4.577
DB - Crossref
ER -
TY - RPRT
TI - Raleigh Durham International Airport Wildlife Hazard Management Plan
AU - Roise, J.P.
AU - Browne, M.
AU - Hertl, P.
A3 - Approved by FAA, study commissioned by RDU
DA - 2012///
PY - 2012///
PB - Approved by FAA, study commissioned by RDU
ER -
TY - JOUR
TI - The effect speed and replenishment flexibility has on overall costs of sourcing apparel products
AU - Hartman, Lisa
AU - Joines, Jeffrey A.
AU - Thoney, Kristin A.
AU - King, Russell E.
T2 - Journal of the Textile Institute
AB - This research investigates the sourcing of basic and seasonal garments as a function of lead time as well as the ability that providing in-season replenishment orders has on overall costs. Most sourcing decisions are made on the basis of the first cost of the garment with little regard to the potential impact of large hidden costs (i.e. lost sales, inventory costs, markdowns, etc.). A small survey administered to apparel manufacturers and retailers is used to gather perspectives on sourcing from various regions of the world. However, its primary purpose is to gather information and data to drive a variety of case studies. The Sourcing Simulator™ is used to determine the effect that lead times, forecasting error, product drift and seasonality have on retail performance (i.e. service levels, gross margins and inventory levels) for these case studies. Analysis is performed to attempt to quantify some of these hidden costs. Results show that choosing suppliers with shorter lead times provides significant advantages for basic goods as well as seasonal goods, which in some instances justify using more expensive suppliers in terms of first cost. These advantages take on the form of smaller inventory levels for achieving the same service, as well as minimizing the impact of errors in forecast and product mix for basic goods while increasing margins by using in-season replenishments for seasonal products.
DA - 2012/6//
PY - 2012/6//
DO - 10.1080/00405000.2011.595106
VL - 103
IS - 6
SP - 604-621
J2 - Journal of The Textile Institute
LA - en
OP -
SN - 0040-5000 1754-2340
UR - http://dx.doi.org/10.1080/00405000.2011.595106
DB - Crossref
KW - supply chain
KW - sourcing decision
KW - inventory models
KW - lead time
ER -
TY - JOUR
TI - The effects of construction related costs on the optimization of steel frames
T2 - Structural Engineering and Mechanics
AB - This paper presents a computational study that explores the design of rigid steel frames by considering construction related costs. More specifically, two different aspects are investigated in this study focusing on the effects of (a) reducing the number of labor intensive rigid connections within a frame of given geometric layout, and (b) reducing the number of different member section types used in the frame. A genetic algorithm based optimization framework searches design space for these objectives. Unlike some studies that express connection cost as a factor of the entire frame weight, here connections and their associated cost factors are explicitly represented at the member level to evaluate the cost of connections associated with each beam. In addition, because variety in member section types can drive up construction related costs, its effects are evaluated implicitly by generating curves that show the trade off between cost and different numbers of section types used within the frame. Our results show that designs in which all connections are considered to be rigid can be excessively conservative: rigid connections can often be eliminated without any appreciable increase in frame weight, resulting in a reduction in overall cost. Eliminating additional rigid connections leads to further reductions in cost, even as frame weight increases, up to a certain point. These complex relationships between overall cost, rigid connections, and member section types are presented for a representative five-story steel frame.
DA - 2012///
PY - 2012///
DO - 10.12989/sem.2012.43.1.031
VL - 43
IS - 1
SP - 31-51
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84863199832&partnerID=MN8TOARS
KW - construction related costs
KW - optimization of moment resisting steel frames
KW - connection cost
KW - member section types
ER -
TY - JOUR
TI - Literature review on superhydrophobic self-cleaning surfaces produced by electrospinning
AU - Sas, Iurii
AU - Gorga, Russell E.
AU - Joines, Jeff A.
AU - Thoney, Kristin A.
T2 - JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS
AB - Abstract Self‐cleaning surface is potentially a very useful addition for many commercial products due to economic, aesthetic, and environmental reasons. Super‐hydrophobic self‐cleaning, also called Lotus effect, utilizes right combination of surface chemistry and roughness to force water droplets to form high contact angle on a surface, easily roll off a surface and pick up dirt particles on its way. Electrospinning is a promising technique for creation of superhydrophobic self‐cleaning surfaces owing to a wide set of parameters that allow effectively controlling roughness of resulted webs. This article gives a brief introduction to the theory of super‐hydrophobic self‐cleaning and basic principles of the electrospinning process and reviews the scientific literature where electrospinning was used to create superhydrophobic surfaces. The article reviewed are categorized into several groups and their results are compared in terms of superhydrophobic properties. Several issues with current state of the art and highlights of important areas for future research are discussed in the conclusion. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
DA - 2012/6/15/
PY - 2012/6/15/
DO - 10.1002/polb.23070
VL - 50
IS - 12
SP - 824-845
SN - 1099-0488
KW - biomimetic
KW - electrospinning
KW - fibers
KW - functionalization of polymers
KW - lotus effects
KW - microstructure
KW - nanotechnology
KW - self-cleaning
KW - superhydrophobic
KW - surfaces
KW - textiles
ER -
TY - BOOK
TI - Simulation Modeling with SIMIO: A Workbook
AU - Joines, J.A.
AU - Roberts, S.D.
DA - 2012///
PY - 2012///
ET - 2nd
PB - Sewickley, PA: SIMIO LLC
ER -
TY - BOOK
TI - Materialized views
AU - Chirkova, R.
AU - Yang, J.
DA - 2012///
PY - 2012///
PB - Boston, [Massachusetts]: now Pub.
ER -
TY - CONF
TI - The latency of gaining alpha-reliability for message dissemination in vehicle-to-vehicle networks
AU - Li, Y. J.
AU - Wang, Wenye
AU - Duel-Hallen, A.
AB - In many Vehicular Ad-hoc Network applications, such as hazard warning and traffic coordination, the message dissemination in unreliable and highly mobile network environment is a key challenge. In order to understand the relationship between dissemination latency and reliability, we analyze the latency of gaining α-reliability that a node correctly receives a message with probability larger than α (0 min (α). Besides dissemination reliability requirement α, t min (α) also depends on node's original distance from the source, node mobility, channel reliability, and traffic flow. Numerical analysis discloses several interesting insights that 1) t min (α) is dominated by the first attempt to send the message to a destination, 2) node mobility has little impact on t min (α) in emergency information dissemination, and 3) transmission range and node density greatly affect dissemination latency and reliability.
C2 - 2012///
C3 - 2012 ieee global communications conference (globecom)
DA - 2012///
DO - 10.1109/glocom.2012.6504004
SP - 5550–5555
ER -
TY - CONF
TI - A fast path-based ILP formulation for offline RWA in mesh optical networks
AU - Liu, Z. Y.
AU - Rouskas, George
AB - RWA is a fundamental problem in the design and control of optical networks. We introduce the concept of symmetric RWA solutions and present a new ILP formulation to construct optimally such solutions. The formulation scales to mesh topologies representative of backbone and regional networks. Numerical results demonstrate that the new formulation achieves a decrease of up to two orders of magnitude in running time compared to existing formulations. In particular, optimal solutions for topologies up to 20 nodes can be obtained within minutes using commodity CPUs, and larger networks can be solved in reasonable time. Our approach significantly lowers the barrier to entry in fully exploring the solution space of optical network design and in investigating the sensitivity of design decisions to forecast demands via extensive “what-if” analysis. Such analysis cannot be carried out currently without large investments in computational resources and time.
C2 - 2012///
C3 - 2012 ieee global communications conference (globecom)
DA - 2012///
DO - 10.1109/glocom.2012.6503572
SP - 2990–2995
ER -
TY - CONF
TI - Hamel's formalism and variational integrators on a sphere
AU - Zenkov, D. V.
AU - Leok, M.
AU - Bloch, A. M.
AB - This paper discusses Hamel's formalism and its applications to structure-preserving integration of mechanical systems. It utilizes redundant coordinates in order to eliminate multiple charts on the configuration space as well as nonphysical artificial singularities induced by local coordinates, while keeping the minimal possible degree of redundancy and avoiding integration of differential-algebraic equations.
C2 - 2012///
C3 - 2012 ieee 51st annual conference on decision and control (cdc)
DA - 2012///
DO - 10.1109/cdc.2012.6426779
SP - 7504-7510
ER -
TY - CONF
TI - Constructing observers for linear time varying DAEs
AU - Bobinyec, Karen
AU - Campbell, Stephen L.
AU - Kunkel, Peter
AB - This paper presents an approach for the construction of both full order and reduced order observers for general linear time varying differential algebraic equations. The necessary theory is presented. Computational issues are elaborated on, and a six dimensional example of an index two electrical circuit is solved as an illustration.
C2 - 2012///
C3 - 2012 IEEE 51st IEEE Conference on Decision and Control (CDC)
DA - 2012///
DO - 10.1109/cdc.2012.6426989
SP - 5749–5754
PB - IEEE
ER -
TY - CONF
TI - Scheduling cloud capacity for time- varying customer demand
AU - Bouterse, B.
AU - Perros, H.
AB - As utility computing resources become more ubiquitous, service providers increasingly look to the cloud for an in-full or in-part infrastructure to serve utility computing customers on demand. Given the costs associated with cloud infrastructure, dynamic scheduling of cloud resources can significantly lower costs while providing an acceptable service level. We investigated several methods for predicting the required cloud capacity in the presence of time-varying customer demand of application environments. We evaluated and compared their performance, using historical data of the Virtual Computing Laboratory (VCL) at North Carolina State University. We show that a simple heuristic, whereby we continuously maintain a fixed reserve capacity, performs better than the other methods.
C2 - 2012///
C3 - 2012 IEEE 1st International Conference on Cloud Networking (cloudnet)
DA - 2012///
DO - 10.1109/cloudnet.2012.6483668
ER -
TY - CONF
TI - Development of distributed grid intelligence platform for solid state transformer
AU - Wang, F.
AU - Lu, X.
AU - Wang, Wenye
AU - Huang, A.
AB - This paper introduces the development of a platform intended as a distributed controller for grid intelligence (DGI) system at FREEDM Systems Center. This platform serves as both a hard real-time local converter controller and a communication node for distributed deployment of energy management schemes. One of the converter devices it controls is the solid state transformer (SST), one of the key elements to interface renewable energy sources into distribution system in FREEDM Center. Both the hardware design and software structure for SST control are presented in this paper. For the communication part, the Distributed Network Protocol (DNP) 3.0 is adopted to congregate multiple SSTs to balance local generation and demands in a coordinated manner. Experiment results are presented to show that this distributed platform has good performance.
C2 - 2012///
C3 - 2012 IEEE Third International Conference on Smart Grid Communications (SmartGridComm)
DA - 2012///
DO - 10.1109/smartgridcomm.2012.6486031
SP - 481–485
ER -
TY - CONF
TI - Density function optimization for the homogenized energy model of shape memory alloys
AU - Crews, J. H.
AU - Smith, Ralph
AB - In this paper, we present two methods for optimizing the density functions in the homogenized energy model (HEM) of shape memory alloys (SMA). The density functions incorporate the polycrystalline behavior of SMA by accounting for material inhomogeneities and localized interaction effects. One method represents the underlying densities for the relative stress and interaction stress as log-normal and normal probability density functions, respectively. The optimal parameters in the underlying densities are found using a genetic algorithm. A second method represents the densities as a linear parameterization of log-normal and normal probability density functions. The optimization algorithm determines the optimal weights of the underlying densities. For both cases, the macroscopic model is integrated over the localized constitutive behavior using these densities. In addition, the estimation of model parameters using experimental data is described. Both optimized models accurately and efficiently quantify the SMA’s hysteretic dependence on stress and temperature, making the model suitable for use in real-time control algorithms.
C2 - 2012///
C3 - Proceedings of the ASME Conference on Smart Materials, Adaptive Structures and Intelligent Systems (SMASIS 2011), vol 1
DA - 2012///
DO - 10.1115/smasis2011-5036
SP - 371–379
ER -
TY - CONF
TI - Output feedback control for continuous-time switched linear systems subject to actuator saturation
AU - Duan, C.
AU - Wu, F.
AB - This paper is devoted to output feedback ℋ∞ control problem for continuous-time switched linear systems subject to actuator saturation. Using minimal switching rule, nonlinear output feedbacks, expressed in the form of quasi-linear parameter varying system are designed to satisfy a pre-specified disturbance attenuation level defined by the regional ℒ2 gains over a class of energy-bounded disturbances. The synthesis condition is further simplified and can be solved through efficient LMI optimizations. The proposed switched control approach is also illustrated by a simple example.
C2 - 2012///
C3 - Proceedings of the ASME Dynamic Systems and Control Conference and Bath/ASME Symposium on Fluid Power and Motion Control (DSCC 2011), vol 1
DA - 2012///
DO - 10.1115/dscc2011-5925
SP - 449-456
ER -
TY - CONF
TI - Nonlinear robust H-infinity control with state-dependent scaling
AU - Hays, S.
AU - Wu, F.
AB - This paper addresses the design of nonlinear robust H∞ controllers for nonlinear uncertain systems with polynomial vector field and norm bounded uncertainties. We derive state-dependent matrix inequalities, using Lyapunov’s direct method, that stabilize the nonlinear systems and guarantee robust performance using nonlinear state-feedback control. The state-dependent synthesis conditions incorporate state-dependent scaling to minimize the ℒ2 gain of the disturbance/output. Sum-of-squares (SOS) optimization is applied to solve the resulting synthesis condition with optimized ℒ2 gain for the nonlinear system, without requiring an iterative approach. Finally, a design example of nonlinear Van der Pol equation is presented.
C2 - 2012///
C3 - Proceedings of the ASME Dynamic Systems and Control Conference and Bath/ASME Symposium on Fluid Power and Motion Control (DSCC 2011), vol 1
DA - 2012///
DO - 10.1115/dscc2011-5994
SP - 581-588
ER -
TY - JOUR
TI - Optimal two-stage procedures for estimating location and size of the maximum of a multivariate regression function
AU - Belitser, E.
AU - Ghosal, S.
AU - Zanten, H.
T2 - Annals of Statistics
DA - 2012///
PY - 2012///
VL - 40
IS - 6
SP - 2850-2876
ER -
TY - CONF
TI - A strain model for piezoelectric materials operating in highly hysteretic regimes
AU - Hu, Z. Z.
AU - Smith, Ralph
AB - Piezoelectric materials exhibit hysteresis in the field-strain relation at essentially all drive levels. Furthermore, this non-linear relation is dependent upon both prestresses and dynamic stresses generated during employment of the materials. The accurate characterization of this nonlinear and hysteretic material behavior is critical for material characterization, device design, and model-based control design. In this paper, we will discuss the characterization of hysteresis using the homogenized energy model (HEM) framework. At the mesoscale, energy relations characterizing field and stress-dependent 90 and 180 degree switching are used to develop fundamental kernels or hysterons. Material and field nonhomogeneities are subsequently incorporated by assuming that certain parameters are manifestations of underlying densities. This yields a macroscopic model that accurately characterizes the fundamental material behavior yet is sufficiently efficient for optimization and control implementation. Attributes of the model will be illustrated through comparison to experimental data.
C2 - 2012///
C3 - Proceedings of the ASME Conference on Smart Materials, Adaptive Structures and Intelligent systems (SMASIS 2011), vol 2
DA - 2012///
DO - 10.1115/smasis2011-5073
SP - 241–249
ER -
TY - CONF
TI - End-to-end delay percentiles for video traces using a MAP2 approximation
AU - Anjum, B.
AU - Perros, H.
AB - Video traffic is widely expected to account for a large portion of the traffic in future wired and wireless networks. We propose an efficient and accurate approximation method for calculating a given percentile of the end-to-end delay of a video stream depicted by a trace. The queueing delay encountered in the network by the IP packets carrying the video is modeled by a tandem queueing network of infinite capacity queues. The video trace is approximated by a two-stage Markovian Arrival Process (MAP2), which is the arrival process to the tandem network. The proposed method uses only the first queue of the tandem queueing network to construct an upper and lower bound of a given percentile of the end-to-end delay. The percentile value is then approximated by interpolating between the two bounds. We used this method to estimate the 95th percentile of the end-to-end delay of two different types of video traces, Cisco's point-to-point presence and WebEx over a 10-node path. The results obtained were compared against simulation, and have an average relative error of 4.24%. Using this method, we then obtained the minimum amount of bandwidth required to be allocated on each link along the path of the video stream, so that a given 95th percentile of the end-to-end delay is satisfied.
C2 - 2012///
C3 - 2012 15th International Telecommunications Network Strategy and Planning Symposium (NETWORKS)
DA - 2012///
DO - 10.1109/netwks.2012.6381676
ER -
TY - CONF
TI - On the connectivity of large multi-channel cognitive radio networks
AU - Sun, L.
AU - Wang, Wenye
AB - Cognitive Radio Networks (CRNs) have become promising network components to improve spectrum utilization efficiency, where secondary (unlicensed) users exploit spectrum opportunistically without interfering with the coexisting primary users. A challenging yet open question is how to ensure that information can be disseminated to the entire CRN, which is a prerequisite to applications of wireless networks. In this paper, we address the connectivity of large multi-channel CRNs. Particularly, we study full connectivity and percolation of secondary networks. The former is the existence of a communication path between any two nodes and the latter is the existence of a large component of secondary users. We find that the sufficient and necessary condition to achieve full connectivity is λ = Θ(log n/πr ^{2} P _{s} ), where λ is the density, n is the number and r is the transmission range of secondary users respectively, and P _{s} is the probability that any two secondary users can communicate with each other without interfering with primary users. We further show that the required density for percolation is a constant, and identify an upper bound on λ, above which the network is percolated and a lower bound on λ below which the network is not percolated. Our results provide a theoretical understanding of connectivity in large multi-channel cognitive radio networks.
C2 - 2012///
C3 - 2012 ieee international conference on communications (icc)
DA - 2012///
DO - 10.1109/icc.2012.6363893
SP - 1854–1858
ER -
TY - JOUR
TI - Numerical Solutions of the System of Singular Integro-Differential Equations in Classical Holder Spaces
AU - Caraus, Iurie
AU - Li, Zhilin
T2 - ADVANCES IN APPLIED MATHEMATICS AND MECHANICS
AB - Abstract New numerical methods based on collocation methods with the mechanical quadrature rules are proposed to solve some systems of singular integro-differential equations that are defined on arbitrary smooth closed contours of the complex plane. We carry out the convergence analysis in classical Hölder spaces. A numerical example is also presented.
DA - 2012/12//
PY - 2012/12//
DO - 10.4208/aamm.12-12s04
VL - 4
IS - 6
SP - 737-750
SN - 2070-0733
KW - Collocation method
KW - classical Holder space
KW - system of singular integro-differential equation
KW - Fejer points
ER -
TY - CONF
TI - Geo-dissemination in vehicular ad hoc networks
AU - Li, Y. J.
AU - Wang, Wenye
AB - Vehicular Adhoc Networks (VANETs) aim to improve road safety and convenience through vehicle-to-vehicle and vehicle-to-roadside communications. Traffic information and accident warnings are often disseminated to vehicles in certain areas where driving could be affected by hazardous situations. Such message dissemination with destinations confined in specific geographic regions is referred to as Geo-Dissemination. In this paper, we analyze how far a geo-dissemination can possibly reach over a period of time t (denoted as dissemination distance D(t)), and what is the latency for a message to reach locations that are d distance far from the source (denoted as the stopping time τ). Simulations results of two dissemination methods (stateless opportunistic forwarding and GPS-based message broadcasting) are compared with our analytic results.
C2 - 2012///
C3 - 2012 ieee international conference on communications (icc)
DA - 2012///
DO - 10.1109/icc.2012.6364456
ER -
TY - CONF
TI - Chunk and object level deduplication for web optimization: A hybrid approach
AU - Papapanagiotou, I.
AU - Callaway, R. D.
AU - Devetsikiotis, M.
AB - Proxy caches or Redundancy Elimination (RE) systems have been used to remove redundant bytes in WAN links. However, they come with some inherited deficiencies. Proxy caches provide less savings than RE systems, and RE systems have limitations related to speed, memory and storage overhead. In this paper we advocate the use of a hybrid approach, in which each type of cache acts as a module in a system with shared memory and storage space. A static scheduler precedes the cache modules and determines what types of traffic should be forwarded to which module. We also propose several optimizations for each of the modules, such that the storage and memory overhead are minimized. We evaluate the proposed system by performing a trace driven emulation. Our results indicate that a hybrid system is able to provide better savings than a proxy cache, or a standalone RE system. The hybrid system requires less memory, less disk space and provides a speed-up ratio equal to three compared to an RE system.
C2 - 2012///
C3 - 2012 ieee international conference on communications (icc)
DA - 2012///
DO - 10.1109/icc.2012.6363843
ER -
TY - CONF
TI - Balancing network connectivity and the life-time of sensors through percolation and consensus
AU - Ban, D.
AU - Devetsikiotis, M.
AB - Due to replacement infeasibility, methods to extend the life-time of sensors have been an issue in Wireless Sensor Networks (WSNs) and these should consider network connectivity simultaneously. Controlling the sleep/awake of sensors is one simple way to reduce their energy consumption. However, this causes a network connectivity degradation by varying network connection topology. For this reason, we propose a simple and autonomous sensor sleep/awake method to achieve their balance. The size of clusters can be a metric to measure network connectivity in that a path exists among any cluster node. From percolation theory, we observe that a cluster size suffers a sharp transition based on edge connection patterns. This allows us to design a sensor sleep/awake algorithm which has an immense simplicity, but still requires global topology information. In many cases, sensors are not aware of the global topology. Further, managing the information becomes challenging under physical topology changes such as sensor add/drop. We show that the global knowledge requirement can be resolved by using a consensus algorithm. Through several graph tests, we show that our method achieves a network balancing between connectivity and life-time with preserving its simplicity. Also, the balancing is autonomous even under physical topology variations.
C2 - 2012///
C3 - 2012 ieee international conference on communications (icc)
DA - 2012///
DO - 10.1109/icc.2012.6364130
ER -
TY - CONF
TI - Average delay SLAs in cloud computing
AU - Saovapakhiran, B.
AU - Devetsikiotis, M.
AU - Michailidis, G.
AU - Viniotis, Y.
AB - In this paper, we conduct feasibility studies on the average delay space for Cloud computing, and we propose a heuristic method to control the vector of average delays, subject to predefined delay constraints. Our work is strongly motivated by the fact that delay control plays a critical role to improve Service Level Agreements (SLA) between users and Cloud service providers, which is necessary for empowering online business. Specifically, our main contributions are two-fold: First, the feasible regions of various routing algorithms for the system's dispatcher are investigated in depth. Second, a simple heuristic algorithm is designed, to move the average delay point along the feasible direction until achieving the delay constraints. Average delay is dependent on multiple factors such as job size, inter-arrival time, flow rate, and the dispatching rules of the system. Therefore, we vary their distribution, parameters and routing rules to examine how the feasible regions move or change. After establishing the feasible delay space, then by moving along the feasible directions, we show that a simple heuristic algorithm can achieve the delay constraints for a two queue system.
C2 - 2012///
C3 - 2012 ieee international conference on communications (icc)
DA - 2012///
DO - 10.1109/icc.2012.6364548
ER -
TY - CONF
TI - An algorithm for joint guidance and power control for electric vehicles in the smart grid
AU - Saovapakhiran, B.
AU - Michailidis, G.
AU - Devetsikiotis, M.
AB - A massive amount of energy consumption currently stems from the transportation sector. Therefore, improvements in power usage by commuting vehicles are being studied and becoming an increasingly popular research topic. In particular, there is a growing need to model the envisioned smart infrastructure, including charging stations, some of which might include energy storage devices and swappable, pre-charged batteries. For such new stations, power management is indeed crucial for operation costs, driver convenience, and overall smart grid efficiency. Information technology, communications and vehicle intelligence need to play a crucial role in this process. In this paper, we describe a quantitative model and propose a guiding and control system for the charging of PHEVs in a future smart infrastructure. Specifically, we describe an algorithm that can be used for the joint guidance and power control of smarter electric vehicles in the smart grid. We envision it as part of a larger Smart Guide for the Smart Grid (SGSG) system. Its function is to guide PHEV drivers, directing them to the appropriate charging station, while attempting to achieve an optimization goal at the same time. Our algorithm aims at a joint guiding and power control, in order to heuristically maximize the weighted sum of the average of throughput and energy cost consumption from multiple vehicle charging stations, while satisfying a cost constraint at each station, as well as system stability.
C2 - 2012///
C3 - 2012 ieee international conference on communications (icc)
DA - 2012///
DO - 10.1109/icc.2012.6364112
ER -
TY - JOUR
TI - Multiple trait multiple interval mapping of quantitative trait loci from inbred line crosses
AU - Silva, L. D. E.
AU - Wang, S. C.
AU - Zeng, Z. B.
T2 - BMC Genetics
DA - 2012///
PY - 2012///
VL - 13
ER -
TY - CONF
TI - Enabling adaptive rate and relay selection for 802.11 mobile ad hoc networks
AU - Mehta, N.
AU - Duel-Hallen, A.
AU - Wang, Wenye
AB - Mobile ad hoc networks (MANETs) are self-configuring wireless networks that lack permanent infrastructure and are formed among mobile nodes on demand. Rapid node mobility results in dramatic channel variation, or fading, that degrades MANET performance. Employing channel state information (CSI) at the transmitter can improve the throughput of routing and medium access control (MAC) protocols for mobile ad hoc networks. Several routing algorithms in the literature explicitly incorporate the fading signal strength into the routing metric, thus selecting the routes with strong channel conditions. While these studies show that adaptation to the time-variant channel gain is beneficial in MANETs, they do not address the effect of the outdated fading CSI at the transmitter. For realistic mobile node speeds, the channel gain is rapidly varying, and becomes quickly outdated due the feedback delay. We analyze the link throughput of joint rate adaptation and adaptive relay selection in the presence of imperfect CSI. Moreover, for an 802.11 network that employs geographic opportunistic routing with adaptive rate and relay selection, we propose a novel method to reduce the effect of the feedback delay at the MAC layer in the presence of Rayleigh fading. This method exploits channel reciprocity and fading prediction and does not require significant modification to the existing 802.11 frame structure. Extensive network simulations demonstrate that the proposed approach significantly improves the throughput, delay, and packet delivery ratio for high mobile velocities relative to previously proposed approaches that employ outdated CSI at the transmitter.
C2 - 2012///
C3 - 2012 ieee international conference on communications (icc)
DA - 2012///
DO - 10.1109/icc.2012.6363785
ER -
TY - JOUR
TI - A Markov Chain Framework for Cycle Time Approximation of Toolsets
AU - Akhavan-Tabatabaei, Raha
AU - Fathi, Yahya
AU - Shanthikumar, J. George
T2 - IEEE TRANSACTIONS ON SEMICONDUCTOR MANUFACTURING
AB - Cycle time is a key performance measure in semiconductor manufacturing. Currently, discrete event simulation and queueing theory are the most common approaches to estimating the cycle time of a fabrication facility. However, the performance of both approaches has been unsatisfactory due to many factors, including the inability to perform in an environment where informal and unwritten operational rules exist. Such rules create dependence between the arrival and service processes of a toolset, and, hence, render the classical queueing models inaccurate. We propose a Markov chain framework that attempts to approximate the cycle time of a toolset in the presence of informal operational rules, and we compare our approach with classical queueing models through a series of numerical examples.
DA - 2012/11//
PY - 2012/11//
DO - 10.1109/tsm.2012.2202252
VL - 25
IS - 4
SP - 589-597
SN - 1558-2345
KW - Markov processes
KW - queueing analysis
KW - stochastic processes
ER -
TY - JOUR
TI - Hybrid Deterministic/Monte Carlo Neutronics using GPU Accelerators
AU - Willert, Jeff
AU - Kelley, C. T.
AU - Knoll, D. A.
AU - Dong, Han
AU - Ravishankar, Mahesh
AU - Sathre, Paul
AU - Sullivan, Michael
AU - Taitano, William
T2 - 2012 11TH INTERNATIONAL SYMPOSIUM ON DISTRIBUTED COMPUTING AND APPLICATIONS TO BUSINESS, ENGINEERING & SCIENCE (DCABES)
AB - In this paper we discuss a GPU implementation of a hybrid deterministic/Monte Carlo method for the solution of the neutron transport equation. The key feature is using GPUs to perform a Monte Carlo transport sweep as part of the evaluation of the nonlinear residual and Jacobian-vector product. We describe the algorithm and present some preliminary numerical results which illustrate the effectiveness of the GPU Monte Carlo sweeps.
DA - 2012///
PY - 2012///
DO - 10.1109/dcabes.2012.37
SP - 43-47
KW - Neutron Transport
KW - Jacobian-Free Newton-Krylov
KW - GPU
KW - Monte Carlo
ER -
TY - JOUR
TI - The nearest point problem in a polyhedral set and its extensions
AU - Liu, Zhe
AU - Fathi, Yahya
T2 - COMPUTATIONAL OPTIMIZATION AND APPLICATIONS
DA - 2012/9//
PY - 2012/9//
DO - 10.1007/s10589-011-9448-5
VL - 53
IS - 1
SP - 115-130
SN - 1573-2894
KW - Quadratic programming
KW - Pos cone
KW - Projection face
KW - Active constraint
ER -
TY - JOUR
TI - The G(t)/GI/s(t)+GI many-server fluid queue
AU - Liu, Yunan
AU - Whitt, Ward
T2 - QUEUEING SYSTEMS
AB - This paper introduces a deterministic fluid model that approximates the many-server G t /GI/s t +GI queueing model, and determines the time-dependent performance functions. The fluid model has time-varying arrival rate and service capacity, abandonment from queue, and non-exponential service and patience distributions. Two key assumptions are that: (i) the system alternates between overloaded and underloaded intervals, and (ii) the functions specifying the fluid model are suitably smooth. An algorithm is developed to calculate all performance functions. It involves the iterative solution of a fixed-point equation for the time-varying rate that fluid enters service and the solution of an ordinary differential equation for the time-varying head-of-line waiting time, during each overloaded interval. Simulations are conducted to confirm that the algorithm and the approximation are effective.
DA - 2012/8//
PY - 2012/8//
DO - 10.1007/s11134-012-9291-0
VL - 71
IS - 4
SP - 405-444
SN - 1572-9443
KW - Queues with time-varying arrivals
KW - Nonstationary queues
KW - Transient behavior
KW - Many-server queues
KW - Deterministic fluid model
KW - Customer abandonment
KW - Non-Markovian queues
ER -
TY - JOUR
TI - Output-feedback control for switched linear systems subject to actuator saturation
AU - Duan, Chang
AU - Wu, Fen
T2 - INTERNATIONAL JOURNAL OF CONTROL
AB - This article is devoted to the output-feedback ℋ∞ control problem for switched linear systems subject to actuator saturation. We consider both continuous- and discrete-time switched systems. Using the minimal switching rule, nonlinear output feedbacks expressed in the form of quasi-linear parameter varying system are designed to satisfy a pre-specified disturbance attenuation level defined by the regional ℒ2 (ℓ2)-gains over a class of energy-bounded disturbances. The conditions are expressed in bilinear matrix inequalities and can be solved by line search coupled with linear matrix inequalities optimisation. A spherical inverted pendulum example is used to illustrate the effectiveness of the proposed approach.
DA - 2012///
PY - 2012///
DO - 10.1080/00207179.2012.691611
VL - 85
IS - 10
SP - 1532-1545
SN - 1366-5820
KW - switching control
KW - output-feedback control
KW - actuator saturation
KW - linear matrix inequalities
ER -
TY - JOUR
TI - Optimal scheduling in multi-server queues with random connectivity and retransmissions
AU - Al-Zubaidy, Hussein
AU - Lambadaris, Ioannis
AU - Viniotis, Yannis
T2 - COMPUTER COMMUNICATIONS
AB - We investigate an optimal scheduling problem in a discrete-time, multiserver system of parallel queues. The servers are connected to the queues in a random fashion and scheduled packets complete service successfully with a given probability. This model is suitable for the study of dynamic packet scheduling problems in wireless systems. We study first a two-server system of two infinite-capacity queues with homogeneous arrival, service and connectivity assumptions. We use coupling arguments to prove that a “Most Balancing” scheduling policy is optimal, in a stochastic ordering sense, for this system. We then consider a finite-capacity, non-homogeneous, multi-server and multi-queue system. We develop a dynamic programming model to determine numerically the scheduling policy that optimizes a range of cost functions, including average total queue sizes. We also compare the performance of the optimal policy to that of a few other policies via simulations.
DA - 2012/7/15/
PY - 2012/7/15/
DO - 10.1016/j.comcom.2012.05.007
VL - 35
IS - 13
SP - 1626-1638
SN - 1873-703X
KW - Optimal scheduling
KW - Stochastic coupling arguments
KW - Stochastic dominance
KW - Most Balancing algorithms
KW - Random connectivity
ER -
TY - JOUR
TI - Introduction to the special issue on optimizing risk management in services
AU - Wu, Desheng Dash
AU - Fang, Shu-Cherng
AU - Olson, David L.
AU - Birge, John R.
T2 - OPTIMIZATION
AB - In recent years, risk management has attracted a great deal of attention from both researchers and practitioners. Complexity and uncertainty in many practical problems require new methods and tools. Risk management can be used as a tool for greater rewards, not just for control against loss. Risks are studied from different silo disciplinary perspectives, with a discussion of how various methods and tools are used to optimize risk management. Enterprise risk management has become an important topic in today's more complex, interrelated global business environment, replete with threats from natural, political, economic and technical sources.
DA - 2012///
PY - 2012///
DO - 10.1080/02331934.2012.724795
VL - 61
IS - 10
SP - 1175-1177
SN - 0233-1934
KW - risk management
KW - optimization
ER -
TY - JOUR
TI - Active Robust Fault Detection in Closed-Loop Systems: Quadratic Optimization Approach
AU - Ashari, A.E.
AU - Nikoukhah, R.
AU - Campbell, S.L.
T2 - IEEE Transactions on Automatic Control
AB - Active fault detection consists of finding an auxiliary input signal such that its use allows detection of faults using a multi-model framework. Faults can be detected during a test period that would otherwise not be possible to detect during normal operation using passive tests. In this paper, we consider the problem of optimal exogenous signal design for a linear uncertain system controlled by a linear feedback. This signal design is based on controller design criteria of linear quadratic regulators (LQR). Optimal exogenous signal design for short test periods is considered first. An efficient method is developed to solve the corresponding finite time-horizon optimization problem. Then the asymptotic behavior of the robust fault detection problem and its stationary optimal solution is considered. The optimal exogenous signal for the stationary case is given based on a frequency analysis of the solution. This signal can be used as an approximation on longer interval finite time-horizons. It is shown that a suitable feedback can reduce the cost function compared with the open-loop case.
DA - 2012/10//
PY - 2012/10//
DO - 10.1109/tac.2012.2188430
VL - 57
IS - 10
SP - 592–605
SN - 1558-2523
KW - Closed-loop systems
KW - detection algorithms
KW - fault detection
KW - feedback
KW - signal design
ER -
TY - JOUR
TI - A many-server fluid limit for the G(t)/GI/s(t) + GI queueing model experiencing periods of overloading
AU - Liu, Yunan
AU - Whitt, Ward
T2 - OPERATIONS RESEARCH LETTERS
AB - A many-server heavy-traffic functional weak law of large numbers is established for the Gt/GI/st+GI queueing model, which has customer abandonment (the +GI), time-varying arrival rate and staffing (the subscript t) and non-exponential service and patience distributions (the two GI’s). This limit provides support for a previously proposed deterministic fluid approximation, and extends a previously established limit for the special case of exponential service times.
DA - 2012/9//
PY - 2012/9//
DO - 10.1016/j.orl.2012.05.010
VL - 40
IS - 5
SP - 307-312
SN - 1872-7468
KW - Many-server heavy-traffic limit
KW - Functional weak law of large numbers
KW - Queues with time-varying arrivals
KW - Nonstationary queues
KW - Deterministic fluid model
KW - Non-Markovian queues
ER -
TY - JOUR
TI - TOWARD SPECIALIZED UNDERGRADUATE TELECOMMUNICATION ENGINEERING EDUCATION IN THE US
AU - El-Bawab, Tarek S.
AU - Esfandiari, Mehran
AU - Rouskas, George
AU - Jayasumana, Anura
AU - Kincaid, Michael
AU - Effenberger, Frank
AU - Kazovsky, Leonid
AU - Medard, Muriel
AU - Frost, Victor
AU - Baniewicz, Paul
T2 - IEEE COMMUNICATIONS MAGAZINE
AB - In ancient times, unless somebody was prepared to travel, man could only communicate as far as he could shout. Methods were then developed to enable communications to extend over longer distances, using trumpets, beacon fire, flags, etc. It was not until the inauguration of telegraphy (by W. Cooke and C. Wheatstone in England in 1839, and by S. Morse in the US in 1844) and telephony (by A. G. Bell in 1876), that electricity was utilized to facilitate commercial telecommunication service [1]-[2]. Then, for nearly 100 years, telecommunications was mainly about telephony and telegraphy and was based almost entirely on electrical engineering methods. From audio to radio signals, electro-mechanic to electronic technologies, analog to digital systems, and electronic to photonic devices; telecommunications has witnessed tremendous progress on numerous fronts. In terms of services and applications, telecommunications evolved in recent years to embrace cyber space, entertainment, and electronic commerce and business.
DA - 2012/9//
PY - 2012/9//
DO - 10.1109/mcom.2012.6295705
VL - 50
IS - 9
SP - 14-16
SN - 0163-6804
ER -
TY - JOUR
TI - A Fiber Bundle Approach to the Transpositional Relations in Nonholonomic Mechanics
AU - Maruskin, Jared M.
AU - Bloch, Anthony M.
AU - Marsden, Jerrold E.
AU - Zenkov, Dmitry V.
T2 - JOURNAL OF NONLINEAR SCIENCE
DA - 2012/8//
PY - 2012/8//
DO - 10.1007/s00332-012-9144-3
VL - 22
IS - 4
SP - 431-461
SN - 1432-1467
KW - Geometric mechanics
KW - Constrained dynamics
KW - Variational principles
ER -
TY - JOUR
TI - Data-driven techniques to estimate parameters in the homogenized energy model for shape memory alloys
AU - Crews, John H.
AU - Smith, Ralph C.
AU - Pender, Kyle M.
AU - Hannen, Jennifer C.
AU - Buckner, Gregory D.
T2 - JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES
AB - The homogenized energy model is a unified framework for modeling hysteresis in ferroelectric, ferromagnetic, and ferroelastic materials. The homogenized energy model framework combines energy analysis at the lattice level with stochastic homogenization techniques, based on the assumption that quantities such as interaction and coercive fields are manifestations of underlying densities, to construct macroscopic material models. In this article, we focus on the homogenized energy model for shape memory alloys. Specifically, we develop techniques for estimating model parameters based on attributes of measured data. Both the local (mesoscopic) and macroscopic models are described, and the model parameters’ relationship to the material’s response is discussed. Using these relationships, techniques for estimating model parameters are presented. The techniques are applied to constant-temperature stress–strain and resistance–strain data. These estimates are used in two manners. In one method, the estimates are considered fixed and only the homogenized energy model density functions are optimized. For SMA, the HEM incorporates densities for the interaction and relative stress (the width of the hysteresis loop). In the second method, the estimates are included in the optimization algorithm. Both cases are compared to experimental data at various temperatures, and the optimized model parameters are compared to the initial estimates.
DA - 2012/11//
PY - 2012/11//
DO - 10.1177/1045389x12453965
VL - 23
IS - 17
SP - 1897-1920
SN - 1530-8138
KW - Shape memory alloys
KW - hysteresis
KW - parameter estimation
ER -
TY - JOUR
TI - Cerebrospinal Fluid Metabolome in Mood Disorders-Remission State has a Unique Metabolic Profile
AU - Kaddurah-Daouk, Rima
AU - Yuan, Peixiong
AU - Boyle, Stephen H.
AU - Matson, Wayne
AU - Wang, Zhi
AU - Zeng, Zhao Bang
AU - Zhu, Hongjie
AU - Dougherty, George G.
AU - Yao, Jeffrey K.
AU - Chen, Guang
AU - Guitart, Xavier
AU - Carlson, Paul J.
AU - Neumeister, Alexander
AU - Zarate, Carlos
AU - Krishnan, Ranga R.
AU - Manji, Husseini K.
AU - Drevets, Wayne
T2 - Scientific Reports
AB - Targeted metabolomics provides an approach to quantify metabolites involved in specific molecular pathways. We applied an electrochemistry-based, targeted metabolomics platform to define changes in tryptophan, tyrosine, purine and related pathways in the depressed and remitted phases of major depressive disorder (MDD). Biochemical profiles in the cerebrospinal fluid of unmedicated depressed (n = 14; dMDD) or remitted MDD subjects (n = 14; rMDD) were compared against those in healthy controls (n = 18; HC). The rMDD group showed differences in tryptophan and tyrosine metabolism relative to the other groups. The rMDD group also had higher methionine levels and larger methionine-to-glutathione ratios than the other groups, implicating methylation and oxidative stress pathways. The dMDD sample showed nonsignificant differences in the same direction in several of the metabolic branches assessed. The reductions in metabolites associated with tryptophan and tyrosine pathways in rMDD may relate to the vulnerability this population shows for developing depressive symptoms under tryptophan or catecholamine depletion.
DA - 2012/9/19/
PY - 2012/9/19/
DO - 10.1038/srep00667
VL - 2
IS - 1
J2 - Sci Rep
LA - en
OP -
SN - 2045-2322
UR - http://dx.doi.org/10.1038/srep00667
DB - Crossref
ER -
TY - JOUR
TI - Analysis of sliver thickness variation from process perturbations in roller drafting
AU - Kim, Jong S.
AU - Suh, Moon W.
AU - Huh, You
T2 - JOURNAL OF THE TEXTILE INSTITUTE
AB - In processing fiber bundles in staple yarn manufacturing, the bundles are doubled and attenuated to an appropriate thickness via drafting. The process conditions are optimized with respect to the fiber and bundle properties. Otherwise, the output fiber bundle becomes non-uniform in its linear density. This research deals with finding the changes in linear density of the output bundle when perturbations are applied to the drafting conditions. Perturbations with specific autocorrelation functions were generated by the random phase spectral method. Along with the stochastically generated test signals, the transient linear density profiles of the fiber bundle in the drafting zone were simulated by using a mathematical model describing the dynamics of the roller drafting, and thus, the linear density of the output bundle could be predicted. Our results showed that the disturbances in input linear density affected the transient profiles of the linear density of the fiber bundle inside the draft zone. It was also shown that the output irregularities were strongly influenced by the perturbation in the input bundle thickness. During drafting, the perturbations in the draft ratio perturbations were not shown to have influenced the transient profiles of the bundle linear density inside the draft zone. However, the variation in the linear density appeared again in the output bundle following exactly the changes in the daft ratio. Disturbances in the process speed, however, were not shown to have influenced the output variation.
DA - 2012///
PY - 2012///
DO - 10.1080/00405000.2012.660754
VL - 103
IS - 10
SP - 1055-1062
SN - 0040-5000
KW - random phase spectral method
KW - autocorrelation
KW - stochastic signals
KW - draft dynamics
KW - disturbances
KW - linear density of fiber bundle
KW - draft ratio
KW - process speed
ER -
TY - JOUR
TI - Viscosity Solution of Optimal Stopping Problem for Stochastic Systems with Bounded Memory
AU - Chang, Mou-Hsiung
AU - Pang, Tao
AU - Pemy, Moustapha
T2 - STOCHASTIC ANALYSIS AND APPLICATIONS
AB - We consider a finite time horizon optimal stopping problem for a system of stochastic functional differential equations with a bounded memory. Under some sufficiently smooth conditions, a Hamilton-Jacobi-Bellman (HJB) variational inequality for the value function is derived via dynamical programming principle. It is shown that the value function is the unique viscosity solution of the HJB variational inequality.
DA - 2012///
PY - 2012///
DO - 10.1080/07362994.2012.727143
VL - 30
IS - 6
SP - 1102-1135
SN - 0736-2994
KW - Optimal stopping
KW - Stochastic control
KW - Stochastic functional differential equations
ER -
TY - CONF
TI - Understanding the tempo-spatial limits of information dissemination in multi-channel cognitive radio networks
AU - Sun, L.
AU - Wang, Wenye
AB - Cognitive Radio Networks (CRNs) have emerged to become promising network components for exploiting spectrum opportunistically in order that information can be delivered in circumstances otherwise impossible. Challenging yet open questions are how fast and how far a packet can be delivered in such networks, in temporal and spatial domains, respectively. The answers to these questions offer a straightforward interpretation of the potentials of CRNs for time-sensitive applications. To tackle these questions, we define two metrics, dissemination radius ∥ℒ(t)∥ and propagation speed S(d). The former is the maximum Euclidean distance that a packet can reach in time t, and the latter is the speed that a packet transmits between a source and destination at Euclidean distance d apart, which can be used to measure the transmission delay. Further, we determine the sufficient and necessary conditions under which there exist spatial and temporal limits of information dissemination in CRNs. We find that when information cannot be disseminated to the entire network, the limiting dissemination radius is statistically dominated by an exponential distribution, while the limiting information propagation speed approaches to zero. Otherwise, the dissemination radius approaches to infinity and the propagation speed S(d) is no lower than some constant k for large d. The results are validated through simulations.
C2 - 2012///
C3 - 2012 Proceedings IEEE infocom
DA - 2012///
DO - 10.1109/infcom.2012.6195489
SP - 1278–1286
ER -
TY - JOUR
TI - The homogenized energy model for characterizing polarization and strains in hysteretic ferroelectric materials: Implementation algorithms and data-driven parameter estimation techniques
AU - Hu, Zhengzheng
AU - Smith, Ralph C.
AU - Ernstberger, Jon
T2 - JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES
AB - Ferroelectric materials, such as lead zirconate titanate, lanthanum-doped lead zirconate titanate, lead manganese niobate, and BaTiO 3 , provide unique actuator and sensor capabilities for applications including nanopositioning, high-speed valves and fuel injectors, camera focusing and shutter mechanisms, ultrasonic devices for biomedical imaging and treatment, and energy harvesting devices. However, to achieve the full potential of the materials, it is necessary to develop and employ models that quantify the creep, rate-dependent hysteresis, and constitutive nonlinearities that are intrinsic to the materials due to their domain structure. The success of models requires that they be highly efficient to implement since real-time applications can require kilo hertz to mega hertz rates. The calibration of models for specific materials, devices, and applications requires efficient and robust parameter estimation algorithms. Finally, control designs can be facilitated by models that admit efficient and robust approximate inversion. The homogenized energy model is a multiscale, micromechanical framework that quantifies a range of hysteretic phenomena intrinsic to ferroelectric, ferromagnetic, and ferroelastic materials. In this article, we present highly efficient implementation and parameter estimation algorithms for the ferroelectric model. This includes techniques to construct analytic Jacobians and data-driven algorithms to determine initial parameter estimates to facilitate subsequent optimization. The efficiency of these algorithms facilitates material and device characterization and provides the basis for constructing efficient and robust inverse algorithms for model-based control design. The model implementation, calibration, and validation are illustrated using rate-dependent lead zirconate titanate data and single-crystal BaTiO 3 data.
DA - 2012/11//
PY - 2012/11//
DO - 10.1177/1045389x12453968
VL - 23
IS - 16
SP - 1869-1894
SN - 1530-8138
KW - Actuator
KW - ferroelectric
KW - hysteresis
KW - piezoelectric
ER -
TY - JOUR
TI - Talent management issues for multinational logistics companies in China: observations from the field
AU - Shi, Yanhong
AU - Handfield, Robert
T2 - INTERNATIONAL JOURNAL OF LOGISTICS-RESEARCH AND APPLICATIONS
AB - With the rapid business expansion in China, multinational logistics companies are desperately in need of local management personnel to staff new offices and routes. This has been a major challenge for multinational logistics enterprises, as finding qualified candidates, recruiting them, and retaining them in China have proven to be harder than expected. Based on a set of interviews with executives in global logistics companies as well as interviews with Chinese supply chain candidates, we explore a set of root causes that underlie the challenges that human resource (HR) managers in multinational logistics companies face when recruiting and retaining Chinese employees. These underlying causes are manifold in nature. First, there is a shortage of qualified graduates from universities for open roles in logistics enterprises partly due to the nascent logistics higher education in China. Second, multinational logistics enterprise roles are often less appealing to talented Chinese job candidates who have multiple options for logistics career opportunities. Third, there is a gap between the expectations of Chinese employees and the perceived reality of foreign managers relative to what constitutes competitive salary, benefits, and job satisfaction conditions. To address the logistics labour challenges, it is imperative that Western logistics enterprises operating in China align their HR strategies and tactics with the hard realities of the Chinese labour pool and the conditions that exist in the market today as well as the near future. We identify several approaches to close the gap that exists today, including (a) creating training opportunities for HR managers on Chinese culture and social contexts, (b) establishing fair incentives internally, and (c) seeking deeper and broader relationships with Chinese universities to attract talent.
DA - 2012///
PY - 2012///
DO - 10.1080/13675567.2012.709488
VL - 15
IS - 3
SP - 163-179
SN - 1469-848X
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84864683366&partnerID=MN8TOARS
KW - multinational logistics
KW - China
KW - recruitment and retention
KW - talent management
ER -
TY - JOUR
TI - Stabilizing Customer Abandonment in Many-Server Queues with Time-Varying Arrivals
AU - Liu, Yunan
AU - Whitt, Ward
T2 - OPERATIONS RESEARCH
AB - An algorithm is developed to determine time-dependent staffing levels to stabilize the time-dependent abandonment probabilities and expected delays at positive target values in the M t /GI/s t + GI many-server queueing model, which has a nonhomogeneous Poisson arrival process (the M t ), has general service times (the first GI), and allows customer abandonment according to a general patience distribution (the +GI). New offered-load and modified-offered-load approximations involving infinite-server models are developed for that purpose. Simulations show that the approximations are effective. A many-server heavy-traffic limit in the efficiency-driven regime shows that (i) the proposed approximations achieve the goal asymptotically as the scale increases, and (ii) it is not possible to simultaneously stabilize the mean queue length in the same asymptotic regime.
DA - 2012///
PY - 2012///
DO - 10.1287/opre.1120.1104
VL - 60
IS - 6
SP - 1551-1564
SN - 0030-364X
ER -
TY - JOUR
TI - STOCHASTIC DATA CLUSTERING
AU - Meyer, Carl D.
AU - Wessell, Charles D.
T2 - SIAM JOURNAL ON MATRIX ANALYSIS AND APPLICATIONS
AB - In 1961 Herbert Simon and Albert Ando [Econometrika, 29 (1961), pp. 111--138] published the theory behind the long-term behavior of a dynamical system that can be described by a nearly uncoupled matrix. Over the past fifty years this theory has been used in a variety of contexts, including queueing theory, brain organization, and ecology. In all of these applications, the structure of the system is known and the point of interest is the various stages the system passes through on its way to some long-term equilibrium. This paper looks at this problem from the other direction. That is, we develop a technique for using the evolution of the system to tell us about its initial structure, and then use this technique to develop an algorithm that takes the varied solutions from multiple data clustering algorithms to arrive at a single data clustering solution.
DA - 2012///
PY - 2012///
DO - 10.1137/100804395
VL - 33
IS - 4
SP - 1214-1236
SN - 1095-7162
KW - cluster analysis
KW - Markov chains
KW - Simon-Ando theory
ER -
TY - CONF
TI - Regularization of linear and nonlinear descriptor systems
AU - Campbell, Stephen
AU - Kunkel, P.
AU - Mehrmann, V.
C2 - 2012///
C3 - Control and optimization with differential-algebraic constraints
DA - 2012///
DO - 10.1137/9781611972252.ch2
SP - 17–36
M1 - 23
ER -
TY - CONF
TI - On latency distribution and scaling: From finite to large cognitive radio networks under general mobility
AU - Sun, L.
AU - Wang, Wenye
AB - Cognitive Radio Networks (CRNs), as a phenomenal technique to improve spectrum efficiency for opportunistic communications, become an integral component in the future communication regime. In this paper, we study the end-to-end latency in CRNs because many CRN applications, such as military networks and emergency networks, are either time-sensitive or dependent on delay performance. In particular, we consider a general mobility framework that captures most characteristics of the existing models and accounts for spatial heterogeneity resulting from the scenario that some locations are more likely to be visited by mobile nodes (these can be home in the case of people, or garage in the case of vehicles). By assuming that secondary users are mobile under this general framework, we find that there exists a cutoff point on the mobility radius #, which indicates how far a mobile node can reach in the spatial domain, below which the latency has a heavy-tailed distribution and above which the tail distribution is bounded by some Gamma (light-tailed) distribution. A heavy tail of the latency implies a significant probability that it takes long time to disseminate a message from the source to the destination and thus a light-tailed latency is crucial for time-critical applications. Moreover, as the network grows large, we notice that the latency is asymptotically scalable (linear) with the dissemination distance (e.g., the number of hops or Euclidean distance). Another interesting observation is that although the density of primary users adversely impacts the expected latency, it makes no influence on the dichotomy of the tail distribution of the latency in finite networks and the linearity of latency in large networks. Our results encourage the CRN deployment for real-time and large applications, when the mobility radius of secondary users is large enough.
C2 - 2012///
C3 - 2012 Proceedings IEEE infocom
DA - 2012///
DO - 10.1109/infcom.2012.6195491
SP - 1287–1295
ER -
TY - JOUR
TI - Monitoring nonlinear profiles using a wavelet-based distribution-free CUSUM chart
AU - Lee, Joongsup
AU - Hur, Youngmi
AU - Kim, Seong-Hee
AU - Wilson, James R.
T2 - INTERNATIONAL JOURNAL OF PRODUCTION RESEARCH
AB - WDFTC is a wavelet-based distribution-free CUSUM chart for detecting shifts in the mean of a profile with noisy components. Exploiting a discrete wavelet transform (DWT) of the mean in-control profile, WDFTC selects a reduced-dimension vector of the associated DWT components from which the mean in-control profile can be approximated with minimal weighted relative reconstruction error. Based on randomly sampled Phase I (in-control) profiles, the covariance matrix of the corresponding reduced-dimension DWT vectors is estimated using a matrix-regularisation method; then the DWT vectors are aggregated (batched) so that the non-overlapping batch means of the reduced-dimension DWT vectors have manageable covariances. To monitor shifts in the mean profile during Phase II operation, WDFTC computes a Hotelling's T 2-type statistic from successive non-overlapping batch means and applies a CUSUM procedure to those statistics, where the associated control limits are evaluated analytically from the Phase I data. Experimentation with several normal and non-normal test processes revealed that WDFTC was competitive with existing profile-monitoring schemes.
DA - 2012///
PY - 2012///
DO - 10.1080/00207543.2012.655865
VL - 50
IS - 22
SP - 6574-6594
SN - 1366-588X
KW - SPC
KW - quality control
KW - statistical methods
KW - profile
KW - CUSUM chart
KW - wavelet transform
ER -
TY - JOUR
TI - Mining Business Contracts for Service Exceptions
AU - Gao, Xibin
AU - Singh, Munindar P.
AU - Mehra, Pankaj
T2 - IEEE TRANSACTIONS ON SERVICES COMPUTING
AB - A contract is a legally binding agreement between real-world business entities whom we treat as providing services to one another. We focus on business rather than technical services. We think of a business contract as specifying the functional and nonfunctional behaviors of and interactions among the services. In current practice, contracts are produced as text documents. Thus the relevant service capabilities, requirements, qualities, and risks are hidden and difficult to access and reason about. We describe a simple but effective unsupervised information extraction approach and tool, Contract Miner, for discovering service exceptions at the phrase level from a large contract repository. Our approach involves preprocessing followed by an application of linguistic patterns and parsing to extract the service exception phrases. Identifying such (noun) phrases can help build service exception vocabularies that support the development of a taxonomy of business terms, and also facilitate modeling and analyzing service engagements. A lightweight online tool that comes with Contract Miner highlights the relevant text in service contracts and thereby assists users in reviewing contracts. Contract Miner produces promising results in terms of precision and recall when evaluated over a corpus of manually annotated contracts.
DA - 2012///
PY - 2012///
DO - 10.1109/tsc.2011.1
VL - 5
IS - 3
SP - 333-344
SN - 1939-1374
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84865696359&partnerID=MN8TOARS
KW - Contract analysis
KW - service exceptions
KW - text mining
ER -
TY - JOUR
TI - Homogenized energy model for characterizing polarization and strains in hysteretic ferroelectric materials: Material properties and uniaxial model development
AU - Smith, Ralph C.
AU - Hu, Zhengzheng
T2 - JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES
AB - Ferroelectric materials, such as lead zirconate titanate, lanthanum-doped lead zirconate titanate, and BaTiO 3 , are being considered, or are already being employed, for a large number of applications including nanopositioning, high-speed valves for fuel injectors, ultrasonic transducers, high-speed camera shutters and autofocusing mechanisms, energy harvesting, and pico air vehicle design. Their advantages include nanometer positioning resolution, broadband frequency responses, moderate power requirements, the capability for miniaturization, and complementary actuator and sensor capabilities. However, they also exhibit creep, rate-dependent hysteresis, and constitutive nonlinearities at essentially all drive levels due to their noncentrosymmetric nature. In this article, we model the hysteretic dependence of strains and polarizations on input fields and stresses using the homogenized energy model framework. At the domain level, the minimization of the Gibbs energy densities yields linear constitutive relations. Nonlinearities and hysteresis due to dipole switching are modeled at the grain level using the Boltzmann theory to specify the evolution of dipole fractions that serve as internal variables. In the final step of the development, stochastic homogenization, based on the assumption that interaction fields and driving forces are manifestations of underlying densities, is used to construct nonlinear constitutive relations for the bulk material. It is demonstrated that these relations are amenable to subsequent development of distributed system models. The article includes significant discussion regarding the mechanisms that produce hysteresis in ferroelectric materials. The capability of the framework for characterizing various hysteretic phenomena, including creep and various rate dependencies, is illustrated by validation with lead zirconate titanate and lanthanum-doped lead zirconate titanate data.
DA - 2012/11//
PY - 2012/11//
DO - 10.1177/1045389x12453967
VL - 23
IS - 16
SP - 1833-1867
SN - 1530-8138
KW - Ferroelectric hysteresis
KW - nonlinear models
ER -
TY - CONF
TI - Hiding traffic with camouflage: Minimizing message delay in the smart grid under jamming
AU - Lu, Z.
AU - Wang, Wenye
AU - Wang, C.
AB - The smart grid is an emerging cyber-physical system that integrates power infrastructures with information technologies. In the smart grid, wireless networks have been proposed for efficient communications. However, the jamming attack that broadcasts radio interference is a primary security threat to prevent the deployment of wireless networks. Hence, spread spectrum systems with jamming resilience must be adapted to the smart grid to secure wireless communications. There have been extensive works on designing spread spectrum schemes to achieve feasible communication under jamming attacks. Nevertheless, an open question in the smart grid is how to minimize message delay for timely communication in power applications. In this paper, we address this problem in a wireless network with spread spectrum systems for the smart grid. By defining a generic jamming process that characterizes a wide range of existing jamming models, we show that the worst-case message delay is a U-shaped function of network traffic load. This indicates that, interestingly, increasing a fair amount of redundant traffic, called camouflage, can improve the worst-case delay performance. We demonstrate via experiments that transmitting camouflage traffic can decrease the probability that a message is not delivered on time in order of magnitude for smart grid applications.
C2 - 2012///
C3 - 2012 Proceedings IEEE infocom
DA - 2012///
DO - 10.1109/infcom.2012.6195760
SP - 3066–3070
ER -
TY - JOUR
TI - Contaminant source characterization in water distribution systems using binary signals
AU - Kumar, Jitendra
AU - Brill, E. Downey
AU - Mahinthakumar, G.
AU - Ranjithan, S. Ranji
T2 - JOURNAL OF HYDROINFORMATICS
AB - This paper presents a simulation–optimization-based method for identification of contamination source characteristics in a water distribution system using filtered data from threshold-based binary water quality signals. The effects of quality and quantity of the data on the accuracy of the source identification methodology are investigated. This study also addresses the issue of non-uniqueness in contaminant source identification under various data availability conditions. To establish the robustness and applicability of the methodology, numerous scenarios are investigated for a wide range of contamination incidents associated with two different networks. Results indicate that, even though use of lower resolution sensors lead to more non-unique solutions, the true source location is always included among these solutions.
DA - 2012/7//
PY - 2012/7//
DO - 10.2166/hydro.2012.073
VL - 14
IS - 3
SP - 585-602
SN - 1465-1734
KW - contaminant warning system
KW - evolutionary algorithms
KW - non-uniqueness
KW - water distribution systems
KW - water quality sensors
ER -
TY - JOUR
TI - Choice as a Principle in Network Architecture
AU - Wolf, Tilman
AU - Griffioen, Jim
AU - Calvert, Ken
AU - Dutta, Rudra
AU - Rouskas, George
AU - Baldine, Ilia
AU - Nagurney, Anna
T2 - ACM SIGCOMM COMPUTER COMMUNICATION REVIEW
AB - There has been a great interest in defining a new network architecture that can meet the needs of a future Internet. One of the main challenges in this context is how to realize the many different technical solutions that have developed in recent years in a single coherent architecture. In addition, it is necessary to consider how to ensure economic viability of architecture solutions. In this work, we discuss how to design a network architecture where choices at different layers of the protocol stack are explicitly exposed to users. This approach ensures that innovative technical solutions can be used and rewarded, which is essential to encourage wide deployment of this architecture.
DA - 2012/10//
PY - 2012/10//
DO - 10.1145/2377677.2377703
VL - 42
IS - 4
SP - 105-106
SN - 1943-5819
KW - Design
KW - network architecture
KW - innovation
KW - economics
ER -
TY - JOUR
TI - Canonical dual approach to solving the maximum cut problem
AU - Wang, Zhenbo
AU - Fang, Shu-Cherng
AU - Gao, David Y.
AU - Xing, Wenxun
T2 - JOURNAL OF GLOBAL OPTIMIZATION
DA - 2012/10//
PY - 2012/10//
DO - 10.1007/s10898-012-9881-8
VL - 54
IS - 2
SP - 341-351
SN - 1573-2916
KW - Global optimization
KW - Maximum cut
KW - Canonical duality
KW - Perturbation method
ER -
TY - JOUR
TI - Advanced oxidation of toluene using Ni-olivine catalysts: Part 1. syntheses, characterization, and evaluation of Ni-olivine catalysts for toluene oxidation
AU - Smith, V. M.
AU - Kolar, P.
AU - Boyette, M. D.
AU - Chinn, M.
AU - Smith, C.
AU - Gangadharan, R.
AU - Zhang, G.
T2 - Transactions of the ASABE
DA - 2012///
PY - 2012///
VL - 55
IS - 3
SP - 1013-1024
ER -
TY - JOUR
TI - A note on power bounded matrices
AU - Hartwig, R. E.
AU - Patricio, P.
T2 - Electronic Journal of Linear Algebra
AB - This research was financed by FEDER Funds through ``Programa Operacional Factores de Competitividade - COMPETE
DA - 2012///
PY - 2012///
DO - 10.13001/1081-3810.1546
VL - 23
SP - 625-645
ER -
TY - JOUR
TI - SOME NEW FINITE DIFFERENCE METHODS FOR HELMHOLTZ EQUATIONS ON IRREGULAR DOMAINS OR WITH INTERFACES
AU - Wan, Xiaohai
AU - Li, Zhilin
T2 - DISCRETE AND CONTINUOUS DYNAMICAL SYSTEMS-SERIES B
AB - Solving a Helmholtz equation $\Delta u + \lambda u = f$efficiently is a challenge for manyapplications. For example, the core part of many efficient solvers for theincompressible Navier-Stokes equations is to solve one or severalHelmholtz equations. In this paper, two new finite difference methodsare proposed for solving Helmholtz equations on irregular domains, orwith interfaces. For Helmholtz equations on irregular domains, theaccuracy of the numerical solution obtained using the existing augmentedimmersed interface method (AIIM) may deteriorate when the magnitude of$\lambda$is large. In our new method, we use a level set function to extendthe source term and the PDE to a larger domain before we apply the AIIM.For Helmholtz equations with interfaces,a new maximum principle preserving finite difference method is developed.The new method still uses the standard five-point stencil with modificationsof the finite difference scheme at irregular grid points. The resulting coefficient matrix of the linear system of finite differenceequations satisfies the signproperty of the discrete maximum principle and can be solved efficientlyusing a multigrid solver. The finite difference method is also extended tohandle temporal discretized equations where the solution coefficient $\lambda$ isinversely proportional to the mesh size.
DA - 2012/6//
PY - 2012/6//
DO - 10.3934/dcdsb.2012.17.1155
VL - 17
IS - 4
SP - 1155-1174
SN - 1531-3492
KW - Helmholtz equation
KW - irregular domain
KW - embedding method
KW - elliptic interface problem
KW - finite difference method
KW - discrete maximum principle
KW - level set function
KW - immersed interface method
KW - augmented IIM
ER -
TY - JOUR
TI - Platys Social: Relating Shared Places and Private Social Circles
AU - Murukannaiah, Pradeep K.
AU - Singh, Munindar P.
T2 - IEEE INTERNET COMPUTING
AB - Social circles can be valuable in online applications, but existing approaches don't readily support such grouping: they either require a user to manually tag connections or offer no more than broad-brush acquaintanceship between connections. Platys Social is a novel approach that learns users' social circles and prioritizes their connections by bringing together contextual information and user interactions. Platys Social runs incrementally, can execute on a resource-limited mobile device, and can potentially avoid storing users' private information on a remote site.
DA - 2012///
PY - 2012///
DO - 10.1109/mic.2011.106
VL - 16
IS - 3
SP - 53-59
SN - 1941-0131
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84858220653&partnerID=MN8TOARS
ER -
TY - JOUR
TI - HEAVY TRAFFIC APPROXIMATIONS OF A QUEUE WITH VARYING SERVICE RATES AND GENERAL ARRIVALS
AU - Buche, Robert
AU - Ghosh, Arka P.
AU - Pipiras, Vladas
T2 - STOCHASTIC MODELS
AB - Heavy traffic limit theorems are established for a class of single server queueing models including those with heavy-tailed or long-range dependent arrivals and time-varying service rates. The models are motivated by wireless queueing systems for which there is an increasing evidence of the presence of heavy-tailed or long-range dependent arrivals, and where the service rates vary with the changes in the wireless medium. The main focus of the paper is to obtain the different possible limit processes that can arise depending on the relationship between scalings for both the arrival and departure processes. The limit processes obtained here are driven by either Brownian motion (when the contribution from the departure process dominates the limit) or the limits of properly scaled arrivals (when the contribution from the arrival process dominates the limit), typical examples being stable Lévy motion or fractional Brownian motion. In particular, for the case where arrival process is given by the infinite source Poisson process, this relationship, which determines the type of the limiting queue-length process, is a simple condition involving the heavy tail exponent, arrival rate and channel variation parameter in the wireless medium model. To establish these limit results, two approaches are studied. In one approach, when the limit is driven by Brownian motion, the perturbed test function method is extended to incorporate reflection. In contrast, the second approach allows for non-Markovian and/or non-Gaussian driving processes in the limit. Both approaches involve averaging in the drift term arising from random service rates at the departures. In the second approach, this averaging is carried out directly and pathwise, thus sidestepping the assumption of driving Brownian motion used in the perturbed test function method.
DA - 2012///
PY - 2012///
DO - 10.1080/15326349.2012.646526
VL - 28
IS - 1
SP - 63-108
SN - 1532-4214
KW - Averaging
KW - Brownian motion
KW - Fractional Brownian motion
KW - Heavy traffic limit theorems
KW - Heavy tails
KW - Long-range dependence
KW - Perturbed test function method
KW - Reflection
KW - Stable Levy motion
KW - Wireless queueing systems
ER -
TY - JOUR
TI - AN AUGMENTED IMMERSED INTERFACE METHOD FOR MOVING STRUCTURES WITH MASS
AU - Ho, Jian
AU - Li, Zhilin
AU - Lubkin, Sharon R.
T2 - DISCRETE AND CONTINUOUS DYNAMICAL SYSTEMS-SERIES B
AB - We present an augmented immersed interface method for simulating the dynamics of a deformable structure with mass in an incompressible fluid. The fluid is modeled by the Navier-Stokes equations in two dimensions. The acceleration of the structure due to mass is coupled with the flow velocity and the pressure. The surface tension of the structure is assumed to be a constant for simplicity. In our method, we treat the unknown acceleration as the only augmented variable so that the augmented immersed interface method can be applied. We use a modified projection method that can enforce the pressure jump conditions corresponding to the unknown acceleration. The acceleration must match the flow acceleration along the interface. The proposed augmented method is tested against an exact solution with a stationary interface. It shows that the augmented method has a second order of convergence in space. The dynamics of a deformable circular structure with mass is also investigated. It shows that the fluid-structure system has bi-stability: a stationary state for a smaller Reynolds number and an oscillatory state for a larger Reynolds number. The observation agrees with those in the literature.
DA - 2012/6//
PY - 2012/6//
DO - 10.3934/dcdsb.2012.17.1175
VL - 17
IS - 4
SP - 1175-1184
SN - 1531-3492
KW - Immersed interface method
KW - augmented method
KW - projection method
KW - Navier-Stokes
KW - moving interface
KW - implicit scheme
KW - fluid-structure
ER -
TY - JOUR
TI - Tractable XML data exchange via relations
AU - Chirkova, Rada
AU - Libkin, Leonid
AU - Reutter, Juan L.
T2 - FRONTIERS OF COMPUTER SCIENCE
AB - We consider data exchange for XML documents: given source and target schemas, a mapping between them, and a document conforming to the source schema, construct a target document and answer target queries in a way that is consistent with the source information. The problem has primarily been studied in the relational context, in which data-exchange systems have also been built. Since many XML documents are stored in relations, it is natural to consider using a relational system for XML data exchange. However, there is a complexity mismatch between query answering in relational and in XML data exchange. This indicates that to make the use of relational systems possible, restrictions have to be imposed on XML schemas and mappings, as well as on XML shredding schemes. We isolate a set of five requirements that must be fulfilled in order to have a faithful representation of the XML data-exchange problem by a relational translation. We then demonstrate that these requirements naturally suggest the in-lining technique for data-exchange tasks. Our key contribution is to provide shredding algorithms for schemas, documents, mappings and queries, and demonstrate that they enable us to correctly perform XML data-exchange tasks using a relational system.
DA - 2012/6//
PY - 2012/6//
DO - 10.1007/s11704-012-2023-0
VL - 6
IS - 3
SP - 243-263
SN - 2095-2236
KW - data exchange
KW - XML
KW - XML shredding
KW - inlining
ER -
TY - JOUR
TI - The Sensitivity Analysis for the Flow Past Obstacles Problem with Respect to the Reynolds Number
AU - Ito, Kazufumi
AU - Li, Zhilin
AU - Qiao, Zhonghua
T2 - ADVANCES IN APPLIED MATHEMATICS AND MECHANICS
AB - Abstract In this paper, numerical sensitivity analysis with respect to the Reynolds number for the flow past obstacle problem is presented. To carry out such analysis, at each time step, we need to solve the incompressible Navier-Stokes equations on irregular domains twice, one for the primary variables; the other is for the sensitivity variables with homogeneous boundary conditions. The Navier-Stokes solver is the augmented immersed interface method for Navier-Stokes equations on irregular domains. One of the most important contribution of this paper is that our analysis can predict the critical Reynolds number at which the vortex shading begins to develop in the wake of the obstacle. Some interesting experiments are shown to illustrate how the critical Reynolds number varies with different geometric settings.
DA - 2012/2//
PY - 2012/2//
DO - 10.4208/aamm.11-m1110
VL - 4
IS - 1
SP - 21-35
SN - 2070-0733
KW - Navier-Stokes equations
KW - sensitivity analysis
KW - flow past cylinder
KW - embedding technique
KW - immersed interface method
KW - irregular domain
KW - augmented system
KW - projection method
KW - fluid-solid interaction
ER -
TY - JOUR
TI - Merging pharmacometabolomics with pharmacogenomics using ‘1000 Genomes’ single-nucleotide polymorphism imputation
AU - Abo, Ryan
AU - Hebbring, Scott
AU - Ji, Yuan
AU - Zhu, Hongjie
AU - Zeng, Zhao-Bang
AU - Batzler, Anthony
AU - Jenkins, Gregory D.
AU - Biernacka, Joanna
AU - Snyder, Karen
AU - Drews, Maureen
AU - Fiehn, Oliver
AU - Fridley, Brooke
AU - Schaid, Daniel
AU - Kamatani, Naoyuki
AU - Nakamura, Yusuke
AU - Kubo, Michiaki
AU - Mushiroda, Taisei
AU - Kaddurah-Daouk, Rima
AU - Mrazek, David A.
AU - Weinshilboum, Richard M.
T2 - Pharmacogenetics and Genomics
AB - Objective We set out to test the hypothesis that pharmacometabolomic data could be efficiently merged with pharmacogenomic data by single-nucleotide polymorphism (SNP) imputation of metabolomic-derived pathway data on a ‘scaffolding’ of genome-wide association (GWAS) SNP data to broaden and accelerate ‘pharmacometabolomics-informed pharmacogenomic’ studies by eliminating the need for initial genotyping and by making broader SNP association testing possible. Methods We previously genotyped 131 tag SNPs for six genes encoding enzymes in the glycine synthesis and degradation pathway using DNA from 529 depressed patients treated with citalopram/escitalopram to pursue a glycine metabolomics ‘signal’ associated with selective serotonine reuptake inhibitor response. We identified a significant SNP in the glycine dehydrogenase gene. Subsequently, GWAS SNP data were generated for the same patients. In this study, we compared SNP imputation within 200 kb of these same six genes with the results of the previous tag SNP strategy as a rapid strategy for merging pharmacometabolomic and pharmacogenomic data. Results Imputed genotype data provided greater coverage and higher resolution than did tag SNP genotyping, with a higher average genotype concordance between genotyped and imputed SNP data for ‘1000 Genomes’ (96.4%) than HapMap 2 (93.2%) imputation. Many low P-value SNPs with novel locations within genes were observed for imputed compared with tag SNPs, thus altering the focus for subsequent functional genomic studies. Conclusion These results indicate that the use of GWAS data to impute SNPs for genes in pathways identified by other ‘omics’ approaches makes it possible to rapidly and cost efficiently identify SNP markers to ‘broaden’ and accelerate pharmacogenomic studies.
DA - 2012/4//
PY - 2012/4//
DO - 10.1097/fpc.0b013e32835001c9
VL - 22
IS - 4
SP - 247-253
J2 - Pharmacogenetics and Genomics
LA - en
OP -
SN - 1744-6872
UR - http://dx.doi.org/10.1097/FPC.0b013e32835001c9
DB - Crossref
KW - 1000 Genomes
KW - HapMap
KW - imputation
KW - major depressive disorder
KW - pharmacometabolomics
KW - pharmacogenomics
KW - selective serotonin reuptake inhibitors
KW - tag single-nucleotide polymorphisms
ER -
TY - JOUR
TI - Global optimal solutions to a class of quadrinomial minimization problems with one quadratic constraint
AU - Yuan, Y. -B
AU - Fang, S. -C.
AU - Gao, D. Y.
T2 - JOURNAL OF GLOBAL OPTIMIZATION
DA - 2012/2//
PY - 2012/2//
DO - 10.1007/s10898-011-9658-5
VL - 52
IS - 2
SP - 195-209
SN - 1573-2916
KW - Nonconvex optimization
KW - Canonical duality
KW - Triality theory
KW - NP-hard problem
KW - Global optimization
ER -
TY - JOUR
TI - A minimal norm corrected underdetermined Gauss-Newton procedure
AU - Campbell, Stephen
AU - Kunkel, P.
AU - Bobinyec, K.
T2 - Applied Numerical Mathematics
AB - If a Gauß–Newton iteration is used to solve a system of equations that has a manifold of solutions, then the iteration does not produce the minimal norm solution. The limit of the iteration depends on the starting point. This paper introduces a modified Gauß–Newton method that is designed to keep the nonunique part of the solution small in some sense. The iteration is analyzed. Its behavior is discussed along with two computational examples that include the iterationʼs application to general integration methods for differential algebraic equations.
DA - 2012///
PY - 2012///
DO - 10.1016/j.apnum.2012.01.006
VL - 62
IS - 5
SP - 592–605
ER -
TY - JOUR
TI - A mathematical biography of Danny C. Sorensen Preface
AU - Benner, Peter
AU - Embree, Mark
AU - Lehoucq, Richard B.
AU - Kelley, C. T.
T2 - LINEAR ALGEBRA AND ITS APPLICATIONS
AB - On the occasion of his 65th birthday, we briefly recount Dan Sorensen’s profound contributions to optimization, numerical linear algebra, and model order reduction for dynamical systems.
DA - 2012/4/15/
PY - 2012/4/15/
DO - 10.1016/j.laa.2012.01.031
VL - 436
IS - 8
SP - 2717-2724
SN - 1873-1856
ER -
TY - JOUR
TI - A MINIMUM EFFORT OPTIMAL CONTROL PROBLEM FOR ELLIPTIC PDES
AU - Clason, Christian
AU - Ito, Kazufumi
AU - Kunisch, Karl
T2 - ESAIM-MATHEMATICAL MODELLING AND NUMERICAL ANALYSIS-MODELISATION MATHEMATIQUE ET ANALYSE NUMERIQUE
AB - This work is concerned with a class of minimum effort problems for partial differential equations, where the control cost is of L∞-type. Since this problem is non-differentiable, a regularized functional is introduced that can be minimized by a superlinearly convergent semi-smooth Newton method. Uniqueness and convergence for the solutions to the regularized problem are addressed, and a continuation strategy based on a model function is proposed. Numerical examples for a convection-diffusion equation illustrate the behavior of minimum effort controls.
DA - 2012///
PY - 2012///
DO - 10.1051/m2an/2011074
VL - 46
IS - 4
SP - 911-927
SN - 1290-3841
KW - Optimal control
KW - minimum effort
KW - L-infinity control cost
KW - semi-smooth Newton method
ER -
TY - JOUR
TI - Special issue on fluid motion driven by immersed structures preface
AU - Layton, A.
AU - Stockie, J.
AU - Li, Z. L.
AU - Huang, H. X.
T2 - Communications in Computational Physics
DA - 2012///
PY - 2012///
VL - 12
IS - 2
SP - I-
ER -
TY - JOUR
TI - Effects of feedback on active fault detection
AU - Ashari, Alireza Esna
AU - Nikoukhah, Ramine
AU - Campbell, Stephen L.
T2 - AUTOMATICA
AB - In recent years there has been increased interest in the use of active approaches for fault detection. In one of these approaches an auxiliary signal is designed such that over a short period it will reveal a fault not otherwise detectable and do so with as little perturbation of system performance as possible. This method is robust in the sense of guaranteeing the detection of the fault for a whole set of bounded uncertainties. Feedback plays an important role in control but its role in active fault detection based on auxiliary signals has not been explored, yet. This paper begins that investigation.
DA - 2012/5//
PY - 2012/5//
DO - 10.1016/j.automatica.2012.02.020
VL - 48
IS - 5
SP - 866-872
SN - 1873-2836
KW - Fault detection
KW - Linear system
KW - Detection systems
KW - Feedback
KW - Optimal detection
ER -
TY - JOUR
TI - An efficient model for the crosscut optimisation problem in a wood processing mill
AU - Fathi, Yahya
AU - Kianfar, Kiavash
T2 - INTERNATIONAL JOURNAL OF PRODUCTION RESEARCH
AB - We propose a dynamic programming model for the crosscut optimisation problem. This problem arises in the context of cutting lumber (rip-first) in order to obtain cubic blocks (cut-pieces) with required dimensions and surface characteristics. We propose a novel approach for matching the pattern of defects on all four surfaces of an incoming strip of wood with the surface requirements of the cut-pieces as specified in a given cut-bill, and determine an effective cutting pattern for each incoming strip accordingly. Our proposed dynamic programming model results in fast execution times as shown by the results of a computational experiment. The model is deployed in a software package that has been implemented successfully in several major rough mills.
DA - 2012///
PY - 2012///
DO - 10.1080/00207543.2010.538446
VL - 50
IS - 2
SP - 485-497
SN - 0020-7543
KW - dynamic programming
KW - cutting stock problem
KW - cutting lumber
ER -
TY - JOUR
TI - An Adaptive Mesh Refinement Strategy for Immersed Boundary/Interface Methods
AU - Li, Zhilin
AU - Song, Peng
T2 - COMMUNICATIONS IN COMPUTATIONAL PHYSICS
AB - An adaptive mesh refinement strategy is proposed in this paper for the Immersed Boundary and Immersed Interface methods for two-dimensional elliptic interface problems involving singular sources. The interface is represented by the zero level set of a Lipschitz function φ(x,y). Our adaptive mesh refinement is done within a small tube of |φ(x,y)|≤ δ with finer Cartesian meshes. The discrete linear system of equations is solved by a multigrid solver. The AMR methods could obtain solutions with accuracy that is similar to those on a uniform fine grid by distributing the mesh more economically, therefore, reduce the size of the linear system of the equations. Numerical examples presented show the efficiency of the grid refinement strategy.
DA - 2012/8//
PY - 2012/8//
DO - 10.4208/cicp.070211.150811s
VL - 12
IS - 2
SP - 515-527
SN - 1991-7120
KW - Adaptive mesh refinement
KW - immersed boundary method
KW - immersed interface method
KW - elliptic interface problem
KW - Cartesian grid method
KW - level set representation
KW - singular sources
ER -
TY - JOUR
TI - A Numerical Method for Solving Elasticity Equations with Interfaces
AU - Hou, Songming
AU - Li, Zhilin
AU - Wang, Liqun
AU - Wang, Wei
T2 - COMMUNICATIONS IN COMPUTATIONAL PHYSICS
AB - Abstract Solving elasticity equations with interfaces is a challenging problem for most existing methods. Nonetheless, it has wide applications in engineering and science. An accurate and efficient method is desired. In this paper, an efficient non-traditional finite element method with non-body-fitting grids is proposed to solve elasticity equations with interfaces. The main idea is to choose the test function basis to be the standard finite element basis independent of the interface and to choose the solution basis to be piecewise linear satisfying the jump conditions across the interface. The resulting linear system of equations is shown to be positive definite under certain assumptions. Numerical experiments show that this method is second order accurate in the L ∞ norm for piecewise smooth solutions. More than 1.5th order accuracy is observed for solution with singularity (second derivative blows up) on the sharp-edged interface corner.
DA - 2012/8//
PY - 2012/8//
DO - 10.4208/cicp.160910.130711s
VL - 12
IS - 2
SP - 595-612
SN - 1991-7120
KW - Elasticity equations
KW - non-body fitted mesh
KW - finite element method
KW - jump condition
ER -
TY - JOUR
TI - Optimal data use in staple yarn manufacturing
AU - Hamilton, B. J.
AU - Oxenham, W.
AU - Hodge, G. L.
AU - Thoney, K. A.
T2 - JOURNAL OF THE TEXTILE INSTITUTE
AB - The contemporary cotton spinning mill is home to modern machinery capable of generating a plethora of data. This data comes in the form of online data, which is real-time data created by the processing machinery, and offline data, which is created via laboratory testing of samples. This paper describes a study which applied statistical techniques to the two data sets. One came from an actual open-end spinning plant. The other was created in a laboratory environment. This analysis served to discover trends within this data sample and to determine the optimal data use for the cotton spinning industry. In addition, the paper presents a perspective into the current state of data management in the cotton spinning industry obtained by visiting an assortment of active spinning mills.
DA - 2012///
PY - 2012///
DO - 10.1080/00405000.2011.588837
VL - 103
IS - 5
SP - 499-507
SN - 0040-5000
KW - product data management
KW - yarn manufacturing
ER -
TY - JOUR
TI - Who's #1?
AU - Langville, Amy N.
AU - Meyer, Carl D.
T2 - SCIENTIFIC AMERICAN
DA - 2012/7//
PY - 2012/7//
DO - 10.1038/scientificamerican0712-21
VL - 307
IS - 1
SP - 21-21
SN - 0036-8733
ER -
TY - JOUR
TI - Sliding Mode Control Design for Hysteretic Ferroelectric Materials
AU - McMahan, Jerry A.
AU - Smith, Ralph C.
T2 - BEHAVIOR AND MECHANICS OF MULTIFUNCTIONAL MATERIALS AND COMPOSITES 2012
AB - Ferroelectric materials are attractive for use in a wide range of applications due to their unique transduction capabilities. However, taking full advantage of these capabilities requires a control design which accounts for the materials' inherent hysteretic behavior. A common approach is to partially cancel the hysteretic effects in the system by employing an approximate inversion algorithm in the control input, resulting in an almost linear system. Using a recently developed modification to the homogenized energy model for ferroelectric materials, we combine this method with a sliding mode control design to track a reference trajectory even in the presence of modeling and inversion errors. Numerical simulations illustrate the effectiveness of the design.
DA - 2012///
PY - 2012///
DO - 10.1117/12.914631
VL - 8342
SP -
SN - 0277-786X
KW - smart systems
KW - hysteresis
KW - sliding mode control
KW - variable structure control
KW - inverse control
ER -
TY - JOUR
TI - Modeling and Bayesian Parameter Estimation for Shape Memory Alloy Bending Actuators
AU - Crews, John H.
AU - Smith, Ralph C.
T2 - BEHAVIOR AND MECHANICS OF MULTIFUNCTIONAL MATERIALS AND COMPOSITES 2012
AB - In this paper, we employ a homogenized energy model (HEM) for shape memory alloy (SMA) bending actuators.
Additionally, we utilize a Bayesian method for quantifying parameter uncertainty. The system consists of a SMA
wire attached to a flexible beam. As the actuator is heated, the beam bends, providing endoscopic motion. The
model parameters are fit to experimental data using an ordinary least-squares approach. The uncertainty in
the fit model parameters is then quantified using Markov Chain Monte Carlo (MCMC) methods. The MCMC
algorithm provides bounds on the parameters, which will ultimately be used in robust control algorithms. One
purpose of the paper is to test the feasibility of the Random Walk Metropolis algorithm, the MCMC method
used here.
DA - 2012///
PY - 2012///
DO - 10.1117/12.914792
VL - 8342
SP -
SN - 1996-756X
KW - shape memory alloys
KW - uncertainty quantificiation
KW - markov chain monte carlo
ER -
TY - JOUR
TI - Generalized framework for personalized recommendations in agent networks
AU - Hang, Chung-Wei
AU - Singh, Munindar P.
T2 - AUTONOMOUS AGENTS AND MULTI-AGENT SYSTEMS
DA - 2012/11//
PY - 2012/11//
DO - 10.1007/s10458-011-9186-1
VL - 25
IS - 3
SP - 475-498
SN - 1573-7454
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84861476514&partnerID=MN8TOARS
KW - Agent mining
KW - Personalized recommendation
KW - Social networks
KW - Ratings networks
KW - Trust
ER -
TY - JOUR
TI - Data-driven techniques to estimate parameters in a rate-dependent ferromagnetic hysteresis model
AU - Hu, Zhengzheng
AU - Smith, Ralph C.
AU - Ernstberger, Jon M.
T2 - PHYSICA B-CONDENSED MATTER
AB - Abstract The quantification of rate-dependent ferromagnetic hysteresis is important in a range of applications including high speed milling using Terfenol-D actuators. There exist a variety of frameworks for characterizing rate-dependent hysteresis including the magnetic model in Ref. [2] , the homogenized energy framework, Preisach formulations that accommodate after-effects, and Prandtl–Ishlinskii models. A critical issue when using any of these models to characterize physical devices concerns the efficient estimation of model parameters through least squares data fits. A crux of this issue is the determination of initial parameter estimates based on easily measured attributes of the data. In this paper, we present data-driven techniques to efficiently and robustly estimate parameters in the homogenized energy model. This framework was chosen due to its physical basis and its applicability to ferroelectric, ferromagnetic and ferroelastic materials.
DA - 2012/5/1/
PY - 2012/5/1/
DO - 10.1016/j.physb.2011.06.084
VL - 407
IS - 9
SP - 1394-1398
SN - 1873-2135
KW - Hysteresis
KW - Ferromagnetic materials
KW - Data-driven estimation techniques
ER -
TY - JOUR
TI - The 1/k-Eulerian polynomials
AU - Savage, C. D.
AU - Viswanathan, G.
T2 - Electronic Journal of Combinatorics
DA - 2012///
PY - 2012///
VL - 19
IS - 1
ER -
TY - JOUR
TI - Randomly generating test problems for fuzzy relational equations
AU - Hu, Cheng-Feng
AU - Fang, Shu-Cherng
T2 - FUZZY OPTIMIZATION AND DECISION MAKING
DA - 2012/3//
PY - 2012/3//
DO - 10.1007/s10700-011-9115-4
VL - 11
IS - 1
SP - 1-28
SN - 1573-2908
KW - Fuzzy relational equations
KW - Triangular norms
KW - Random generator
ER -
TY - JOUR
TI - Impact factor as a metric to assess journals where OM research is published
AU - Stonebraker, Jeffrey S.
AU - Gil, Esther
AU - Kirkwood, Craig W.
AU - Handfield, Robert B.
T2 - JOURNAL OF OPERATIONS MANAGEMENT
AB - Highlights ► We conducted an exhaustive comparison of OM journal rankings based on impact factors versus other ranking methods (113 characters) ► Impact factors are useful metrics to rank OM journals (53 characters) ► Impact factor rankings alone are not a replacement for survey‐based, citation‐based, or author‐based methods (108 characters) ► Impact factors evaluate OM journal quality from another perspective and can be used with other methods to rank OM journals (122 characters) ► Impact factors are likely to shape and influence future perception of OM journal quality (88 characters) This paper investigates impact factor as a metric for ranking the quality of journal outlets for operations management (OM) research. We review all prior studies that assessed journal outlets for OM research and compare all previous OM journal quality rankings to rankings based on impact factors. We find that rankings based on impact factors that use data from different time periods are highly correlated and provide similar rankings of journals using either two‐year or five‐year assessment periods, either with or without self‐citations. However, some individual journals have large rank changes using different impact factor specifications. We also find that OM journal rankings based on impact factors are only moderately correlated with journal quality rankings previously determined using other methods, and the agreement among these other methods in ranking the quality of OM journals is relatively modest. Thus, impact factor rankings alone are not a replacement for the assessment methods used in previous studies, but rather they evaluate OM journals from another perspective.
DA - 2012/1//
PY - 2012/1//
DO - 10.1016/j.jom.2011.05.002
VL - 30
IS - 1-2
SP - 24-43
SN - 1873-1317
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84857369472&partnerID=MN8TOARS
KW - Operations management
KW - Production operations management
KW - Impact factor
KW - Citation analysis
KW - Journal ranking
ER -
TY - JOUR
TI - CONVEX OPTIMIZATION ON MIXED DOMAINS
AU - Adivar, Murat
AU - Fang, Shu-Cherng
T2 - JOURNAL OF INDUSTRIAL AND MANAGEMENT OPTIMIZATION
AB - This paper aims to study convex analysis on some “generalized domains,” in particular, the domain of the product of closed subsets of reals. We introduce the basic concepts and derive analytic properties regarding convex subsets of mixed domains and convex functions defined on convex sets in mixed domains. The results obtained may open an avenue for modeling and solving a new type of optimization problems that involve both discrete and continuous variables at the same time.
DA - 2012/2//
PY - 2012/2//
DO - 10.3934/jimo.2012.8.189
VL - 8
IS - 1
SP - 189-227
SN - 1553-166X
KW - Continuous optimization
KW - convexity
KW - convex optimization
KW - discrete optimization
KW - generalized convexity
KW - subgradient
KW - time scales
ER -
TY - JOUR
TI - A TROPICAL CYCLONE-BASED METHOD FOR GLOBAL OPTIMIZATION
AU - Chao, Chien-Wen
AU - Fang, Shu-Cherng
AU - Liao, Ching-Jong
T2 - JOURNAL OF INDUSTRIAL AND MANAGEMENT OPTIMIZATION
AB - This paper proposes a new heuristic, Tropical Cyclone-based Method (TCM), for solving global optimization problems with box constraints. TCM mimics the formation process of tropical cyclones in the atmosphere to move a set of sample points towards optimality. The formation of a tropical cyclone in nature is still not completely understood by people. Nevertheless, inspired by the known formation factors of a tropical cyclone, TCM is designed to seek optimal solutions by considering airflow, disturbance, and convection in order to traverse the solution space. Experimental results on some well-known nonlinear test functions are included. Compared with the well-known Electromagnetism-like Mechanism (EM), TCM is both effective and efficient for solving the reported test functions.
DA - 2012/2//
PY - 2012/2//
DO - 10.3934/jimo.2012.8.103
VL - 8
IS - 1
SP - 103-115
SN - 1553-166X
KW - Global optimization
KW - tropical cyclone
KW - population-based search
KW - heuristics
KW - soft computing.
ER -
TY - JOUR
TI - Mahonian pairs
AU - Sagan, Bruce E.
AU - Savage, Carla D.
T2 - JOURNAL OF COMBINATORIAL THEORY SERIES A
AB - We introduce the notion of a Mahonian pair. Consider the set, P ⁎ , of all words having the positive integers as alphabet. Given finite subsets S , T ⊂ P ⁎ , we say that ( S , T ) is a Mahonian pair if the distribution of the major index, maj, over S is the same as the distribution of the inversion number, inv, over T . So the well-known fact that maj and inv are equidistributed over the symmetric group, S n , can be expressed by saying that ( S n , S n ) is a Mahonian pair. We investigate various Mahonian pairs ( S , T ) with S ≠ T . Our principal tool is Foataʼs fundamental bijection ϕ : P ⁎ → P ⁎ since it has the property that maj w = inv ϕ ( w ) for any word w . We consider various families of words associated with Catalan and Fibonacci numbers. We show that, when restricted to words in { 1 , 2 } ⁎ , ϕ transforms familiar statistics on words into natural statistics on integer partitions such as the size of the Durfee square. The Rogers–Ramanujan identities, the Catalan triangle, and various q -analogues also make an appearance. We generalize the definition of Mahonian pairs to infinite sets and use this as a tool to connect a partition bijection of Corteel–Savage–Venkatraman with the Greene–Kleitman decomposition of a Boolean algebra into symmetric chains. We close with comments about future work and open problems.
DA - 2012/4//
PY - 2012/4//
DO - 10.1016/j.jcta.2011.11.003
VL - 119
IS - 3
SP - 526-545
SN - 0097-3165
KW - Ballot sequence
KW - Greene-Kleitman symmetric chain decomposition
KW - Foata's fundamental bijection
KW - Integer partition
KW - Inversion number
KW - Mahonian statistic
KW - Major index
KW - Rank of a partition
KW - q-Catalan number
KW - q-Fibonacci number
ER -
TY - JOUR
TI - An Experimental Comparison of Production Planning Using Clearing Functions and Iterative Linear Programming-Simulation Algorithms
AU - Kacar, Necip Baris
AU - Irdem, Durmus Fatih
AU - Uzsoy, Reha
T2 - IEEE TRANSACTIONS ON SEMICONDUCTOR MANUFACTURING
AB - We compare the performance of three algorithms for production planning with workload-dependent lead times. These include a clearing function model using two different methods for estimating the clearing functions, and two iterative algorithms that combine linear programming and simulation models. Our experimental comparison uses a simulation model of a re-entrant bottleneck system built with attributes of a real-world semiconductor fabrication environment. We vary the bottleneck utilization, demand patterns, the mean time to failure, and the mean time to repair. Results indicate that the clearing function model performs better than the iterative algorithms on the scaled-down system considered, giving less variable production plans and higher profit values.
DA - 2012/1//
PY - 2012/1//
DO - 10.1109/tsm.2011.2176560
VL - 25
IS - 1
SP - 104-117
SN - 0894-6507
KW - Clearing function
KW - linear programming (LP)
KW - production planning
KW - simulation
KW - workload-dependent lead times
ER -
TY - JOUR
TI - Univariate cubic L-1 interpolating splines based on the first derivative and on 5-point windows: analysis, algorithm and shape-preserving properties
AU - Jin, Qingwei
AU - Yu, Lu
AU - Lavery, John E.
AU - Fang, Shu-Cherng
T2 - COMPUTATIONAL OPTIMIZATION AND APPLICATIONS
DA - 2012/3//
PY - 2012/3//
DO - 10.1007/s10589-011-9426-y
VL - 51
IS - 2
SP - 575-600
SN - 1573-2894
KW - Cubic L-1 spline
KW - First-derivative-based
KW - Interpolation
KW - Locally calculated
KW - Shape preservation
ER -
TY - JOUR
TI - Locally Invertible Multidimensional Convolutional Encoders
AU - Lobo, Ruben
AU - Bitzer, Donald L.
AU - Vouk, Mladen A.
T2 - IEEE TRANSACTIONS ON INFORMATION THEORY
AB - A polynomial matrix is said to be locally invertible if it has an invertible subsequence map of equal size between its input and output sequence spaces. This paper examines the use of these matrices, which we call locally invertible encoders, for generating multidimensional convolutional codes. We discuss a novel method of encoding and inverting multidimensional sequences using the subsequence map. We also show that the overlapping symbols between consecutive input subsequences obtained during the sequence inversion can be used to determine if the received sequence is the same as the transmitted codeword.
DA - 2012/3//
PY - 2012/3//
DO - 10.1109/tit.2011.2178129
VL - 58
IS - 3
SP - 1774-1782
SN - 1557-9654
KW - Convolutional codes
KW - error correction codes
KW - multidimensional systems
ER -
TY - JOUR
TI - Koko: an architecture for affect-aware games
AU - Sollenberger, Derek J.
AU - Singh, Munindar P.
T2 - AUTONOMOUS AGENTS AND MULTI-AGENT SYSTEMS
DA - 2012/3//
PY - 2012/3//
DO - 10.1007/s10458-010-9160-3
VL - 24
IS - 2
SP - 255-286
SN - 1387-2532
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84855538746&partnerID=MN8TOARS
KW - Architecture
KW - Affect
KW - Games
KW - Emotion
ER -
TY - JOUR
TI - Ehrhart series of lecture hall polytopes and Eulerian polynomials for inversion sequences
AU - Savage, Carla D.
AU - Schuster, Michael J.
T2 - JOURNAL OF COMBINATORIAL THEORY SERIES A
AB - For a sequence s=(s1,…,sn) of positive integers, an s-lecture hall partition is an integer sequence λ satisfying 0⩽λ1/s1⩽λ2/s2⩽⋯⩽λn/sn. In this work, we introduce s-lecture hall polytopes, s-inversion sequences, and relevant statistics on both families. We show that for any sequence s of positive integers: (i) the h⁎-vector of the s-lecture hall polytope is the ascent polynomial for the associated s-inversion sequences; (ii) the ascent polynomials for s-inversion sequences generalize the Eulerian polynomials, including a q-analog that tracks a generalization of major index on s-inversion sequences; and (iii) the generating function for the s-lecture hall partitions can be interpreted in terms of a new q-analog of the s-Eulerian polynomials, which tracks a “lecture hall” statistic on s-inversion sequences. We show how four different statistics are related through the three s-families of partitions, polytopes, and inversion sequences. Our approach uses Ehrhart theory to relate the partition theory of lecture hall partitions to their geometry.
DA - 2012/5//
PY - 2012/5//
DO - 10.1016/j.jcta.2011.12.005
VL - 119
IS - 4
SP - 850-870
SN - 1096-0899
KW - Lecture hall partitions
KW - Eulerian polynomials
KW - Permutation statistics
KW - Ehrhart-theory
KW - Inversion sequences
KW - q-Series identities
ER -
TY - JOUR
TI - A direct sampling method to an inverse medium scattering problem
AU - Ito, Kazufumi
AU - Jin, Bangti
AU - Zou, Jun
T2 - INVERSE PROBLEMS
AB - In this work we present a novel sampling method for time harmonic inverse medium scattering problems. It provides a simple tool to directly estimate the shape of the unknown scatterers (inhomogeneous media), and it is applicable even when the measured data are only available for one or two incident directions. A mathematical derivation is provided for its validation. Two- and three-dimensional numerical simulations are presented, which show that the method is accurate even with a few sets of scattered field data, computationally efficient, and very robust with respect to noises in the data.
DA - 2012/2//
PY - 2012/2//
DO - 10.1088/0266-5611/28/2/025003
VL - 28
IS - 2
SP -
SN - 1361-6420
ER -
TY - JOUR
TI - A canonical dual approach for solving linearly constrained quadratic programs
AU - Xing, Wenxun
AU - Fang, Shu-Cherng
AU - Sheu, Ruey-Lin
AU - Wang, Ziteng
T2 - EUROPEAN JOURNAL OF OPERATIONAL RESEARCH
AB - This paper provides a canonical dual approach for minimizing a general quadratic function over a set of linear constraints. We first perturb the feasible domain by a quadratic constraint, and then solve a “restricted” canonical dual program of the perturbed problem at each iteration to generate a sequence of feasible solutions of the original problem. The generated sequence is proven to be convergent to a Karush–Kuhn–Tucker point with a strictly decreasing objective value. Some numerical results are provided to illustrate the proposed approach.
DA - 2012/4/1/
PY - 2012/4/1/
DO - 10.1016/j.ejor.2011.09.015
VL - 218
IS - 1
SP - 21-27
SN - 1872-6860
KW - Quadratic programming
KW - Global optimization
KW - Canonical duality theory
ER -